Domain

Explanation

What FYP?

• FYP stands for Final Year Project
• In honours courses in universities, the last year of studies is commonly occupied by a pan-year project on a specific, focused research topic of interest to the faculty of studies & student’s aptitude

What lessons?

• Learning is conducted at all stages of the FYP experience as a form of studies:

1. Preparation stage
2. Planning stage
3. Implementation or Execution stage
4. Reporting stage
5. Defence stage
6. Evaluation stage

• Within each of the above six typical stages of any project, there are valuable lessons that can be picked up along the way
• Just memories are made along experiences & holidays
• This remains true even between adjacent stages

FYP lessons

• Below are the chronological diary of FYP experiences that I have managed to pick up à it can prove to be quite helpful

23/8

• 1^st week: friendly atmosphere, but tinged with a mood of caution, difficulties & uncertainties

30/8

• 2^nd week: further caution à need to speed up à dive directly into project needs & preparation, while picking up the fundamentals of dynamics basics, vibration control concepts & experimentation aspects
• Remain focused on technical issues, avoid all & any personal issues (remember conflict management)

6/9

• 3^rd week: FYP route à schedule quarters à clarity of objectives, scope & action (strategy)
• Vibration control concepts & implementation: linear structure + linear control
• Effects of linear optimal control (LQR): trade-off between states & acc. à use active means only when passive & semi-active means are exhausted
• FFT: EQ à frequency PSD plots à low frequencies high: deep clay à low stiffness, high w
• Damping & stiffness effective only for relative motion à passive & semi-active means concentrated @ locations with largest relative motions
• LQR procedure: system dynamics à S.S. à excitation: known or instantaneous à sensor à controller à actuator à closed-loop simulation
• Preliminary simulation: SDOF à LQR à plots of responses & controls
• Control aspects:
• Physical devices:
• Passive
• Semi-active
• Active
• Controllers:
• Nominal
• Robust
• Adaptive
• Configurations:
• Hybrid control
• Composite control

Management: 2 & 5, let's keep this straight ... your internal email should not come to me or the supervisors ... my batch tried it before ... & e consensus is that all programs, codes & results should not be email ... but only presented conscientiously during meetings ... remember e weekly meeting is not some FAQ .. but a chance to train your focus that is invaluable for thesis writing & presentation skills

13/9

• 4^th week: benchmark problem à simulations à reduced order modelling (Qu et al) à sensor {nos, locations, model} à controller (parametric studies) à actuator {nos, locations, model} à results {parameters, figures, tables, Matlab files}
• DHL
• Focus on technical issues, avoid personal ones unless for relaxation
• Selection of actuators (sensors) is separated & different from actual usage (controls of actuators & measurements by sensors)
• Expt: piezo relations, calibration (objectives à verify properties & derive N/V conversion ratio graphs, nos & locations required), set-up (column base, braces or top-connected)
• Num: LQR weights on energies (WSY) à benchmark flowchart à dynamics solution (Newmark-b ) à bilinear model control:
• 2 linear models & state-space models
• E₁ & E₂<E₁: decreasing stiffness
• Constant mass & damping
• Set transition displacement: x_t
• LQR gains:
• Simulations: uncontrolled à nominal linear controlled à non-linear controlled
• Too many questions & meetings: asking for help, direction & concerns (about thesis scope, depth) à give a broad overview à highlights the difficulties & complexities involved à understand that R&D is basic, bottom-up (from known to unknown, from simple to complex, from trial problem to real problem, from formulations to numerical to experimental)
• LQR: linear controls for linear state space, but actual system need not be linear

20/9

• 5,
  objective: to realise (verify all formulations) numerically with robust LQR controller for the benchmark problem (Ohtori et al 2001)
  intermediate step (tools): verify controller parameters for a SDOF bilinear system, then 2DOF & dynamic condensation
• 2,
  objective: to realise (make SDOF set-up work) experimentally with robust LQR controller using piezoelectric sensors & actuators (Kamada et al 1997)
  intermediate step (tools): Labview interfacing, actuator sourcing & calibration
• Lai,
  objective: To control dynamic response of an unbraced frame under ground excitations with parametric uncertainties and bounded disturbances for minimal energy requirement & optimal stable performance using a network of independent decentralized subsystem controllers, each with sensors and force-inserting stacked actuators
  intermediate step (tools): structural knowledge, modern control knowledge, robust reliable controller (for FYP), adaptive controller (for non-linear systems), unification (of both controllers), verifications

• Numerical expansion:
• Bottom, middle & top SDOF: parametric studies
• Bilinear model
• Model reduction & modal condensation: compare Qu, Ritz (deterministic & stochastic)
• Robust reliable LQR: parametric studies
• Layering for bilinear model: K₁ à MRAS à K₂
• Experimental expansion:
• Non-linear: MPA Chopra
• 2DOF: translation & rotation for Kamada et al 1998
• Multi-bay structure
• Column buckling using follower force

27/9

• Seminar: water reclamation Ong Say 4

4/10

• Seminar: ITS Quek Song Kim

11/10

• 5: programming errors:
• Syntax error: command usage
• I/O error: garbage in, garbage out - read or process or print out wrongly
• Logic error: algorithm design, structuring & organisation
• Experience emotional repulsive reflex syndrome: avoid technical issues, meetings & people at costs of lying & non-cooperation
• Solution: let him rest & recuperate, forcing has no use & all detriment, in future, bring out all alternatives & let him & him only choose which & how he likes to do it
• 2: dynamics difficulties
• Actuator transfer dynamics: p_f(t)
• Actuator dynamics: K_fj(t)
• Fundamental slope-deflection derivation
• Apply to seismic transfer dynamics
• Shake table
• Piezoelectric actuator calibration difficulties: set-up, soldering wires, precompression & just testing piezo effects (sensing) & inverse piezo effects (actuating)
• Both having difficulties, but tell them not to be overwhelmed … it’s okay & expected … do one step at a time … no more no less … keep at it
• Difficulties … can & always must seek help … help as in … people (must approach the right person in right way in right place at right time) … internet … books, texts, notes … derive … theory of inventive problem solving

18/10

• Stuck-up emotions when Prof Quek persistently points own shortcomings:
• Offering a FYP project (experimental): without first trying & at least making it work for the simplest case
• Inability to adapt to new & often-conflicting challenges: research means giving up "insurance" mentality of "spoon-feeding" of what is "right" ways & means to conduct
• 5 notices stuck-up & persistently gives striking phrases "I see"
• 2 has shaking fingers as he explains – stuck up worries about other things & personal conflicts
• Solution approach: willingly & happily admit own mistakes & abuses myself in front of them
• Atmosphere needs to be harmonious before labour can bear fruits

20/11

• Vibration controls is serviceable
• General most used: structural design, passive damping
• Specialist used: semi-active to active controls à low frequencies, exotic excitations, very expensive & less realistic
• Applications:
• Research: workability focus, less on realism
• Engineering: practicality focus, less on exotic, cosmetic research
• 1^st principle of learning:
• Principle of inference: states that the focus of learning is actually on skills exogenous or endogenous to the current skills on-hand
• Piezo calibration difficulties:
• Piezo: specifications, operating frequencies & amplitudes, bounded limits, (N-V-Hz-extension)
• Set-up
• Mechanism: column-base control
• System & excitation: cantilever on shake table (new research engineer employed)

• 3 strategies:

1. Up: scale down EQ à stiffened system à lower peak actuation demands à lesser precompression required à lesser voltage à less stringent sampling & equipment needs à same mechanism & piezo & methodology
2. Medium: same piezo, but different mechanism à actuation transfer mechanism changed à e.g. coupled buildings à toggle-braces
3. Down: different actuator & mechanism à e.g. MR damper

• Engineering is tough, pragmatic techno-social science

21/11

2,

regarding yr questions:

• Force equilibrium or displacement approach: Both are equivalent ... i.e. if we use Force Method (assume force equilibrium, impose compatibility), the dynamic equation is exactly same as Displacement Method (assume compatibility, impose equilibrium; e.g. Stiffness method) --> this is because both are consistent & can be derived from Energy Approach (Conservation of Energy) fundamentals --> whether we use either force or displacement, the dynamic results must be the same --> our M,C,K dynamic equation is actually an extension of the Stiffness Method (static) --> hence, displacement method (which is unique, as compared to force method which is non-unique) 
• Effect of actuation: 1) increase overall stiffness (k+A) --> stiffen system --> harder to displace from equilibrium; 2) increase damping (c+Aw) --> damping means energy loss from EQ-excited system --> use active means to apply energy to cancel out excitation energy --> i.e. similar to waves --> excitation waves are canceled out by almost perfectly anti-excitation waves [N.B. this is an expensive way - Xia strategy]; 3) Decrease inertia (m-Aw^2) --> less inertia --> less energy transmitted to lumped mass --> less excited acceleration --> less exponential effects on velocity & displacement
• Effect of fixing actuator operating amplitude (A) & varying frequency (w): actuator is operated as a relay --> constant amplitude --> time-varying w --> switching between the extremes of amplitude by the frequencies --> relay is like a switch --> jumping between amplitudes depending on feedback requirements

22/11

2,

we r wrong just now ... our F=Fosinwt ... this (F) is the actuation force ... just now, we take it only as a stiffness force, neglecting the (damping) & (inertia) components ... here's how to ensure that all components are included, such that we can have damping (w) & inertia (w^2) inside:

Let F = ka.x + ca.v + ma.acc

where

x,v,acc: piezo relative displacement, velocity & acceleration

ka: piezo stiffness

ca: piezo damping coefficient

ma: piezo inertia

note:

x=x0.snwt, where x0: operating amplitude; w: operating frequency --> x0: is very small .. yes

v=xdot = x0w.coswt --> note w is inside the velocity amplitude --> amplitude=x0.w --> even with a small x0, w can be made arbitrarily large to achieve required damping effect (amplitude)

acc=vdot = -x0w^2.sinwt --> now w^2 is even larger --> even more actuation effect --> note the negative sign: piezo Decreases the overall mass of the system --> (K)/(new mass) is even larger than (K)/(old mass)

With this, substitute into the energy balance equation (Wong):

Wi + Wd + Ws + Wa + We = constant

where

Wi: inertia or kinetic energy

Wd: system damping or energy loss from system

Ws: stiffness or strain energy

Wa: actuation energy = integral of (F.v)dt --> note the velocity would ensure cancellation

We: excitation energy --> zero if ground is fixed

Dynamic equation would surface, then overall system becomes (the form is something like):

(M - ma.x0.w^2) (xdd) + (C + ca.w) (xd) + (K + ka) (x) = 0

hence, mass decreases, damping & stiffness increases:

stiffness effect small

damping effect: magnified by (w)

inertia effect: magnified by (w^2)

For optimal w,

take implicitt differentiation

impose dx/dw=0 --> optimal w

25/11

• Three major concerns for practical engineer:
• Statics vs. Dynamics (2^nd order, higher order, modelling, formulation, solution)
• Linear vs. Non-linear (polynomial, sinusoidal)
• Elastic vs. Inelastic (yielding, elastic-plastic, elasto-plastic, fatigue, creep, ductility, collapse, post-collapse)
• Interaction analogy of piezo Force-Displacement-Voltage:
• Analogy of BS steel interaction surface
• Methodologies:
• Analytical: piezo constitutive equations (linear)
• Numerical
• Experimental: piezo verification
• Approach methodology:
• Force equilibrium: when displacement is not a constraint
• Displacement equilibrium: when force is not a constraint
• Energy conservation: in terms of sinusoidal harmonics à to derive equilibrium à determine piezo operating amplitudes & frequencies

9/12

• Scope: major thrust
• 2:

1. Piezoelectric actuator calibration
2. Labview interfacing & controller
3. Shake table identification & experiment

• 5:

1. Bilinear: SDOF, 2DOF
2. MDOF controls: LQRx, LQRy
3. Hysteresis

1^st Law of ReSearch

1. General research papers: survey, comparison, overview or collection of historical, current & potential future developments --> For: the big picture, get an idea of the state-of-the-art, discover or uncover loop-holes or niches for us to explore & exploit --> e.g. for our cases, we need survey of seismic structural design, isolation & control --> then, control is surveyed for passive, semi-active & active --> split into theory, R&D, constructed & commercialised
2. Specific complementary papers: detailed papers targeted & focused on their narrow objectives & scope that fits our needs --> e.g. Kamada et al 1998 researches (active control), for (Frames), (EQ), using (piezo) sensors & actuators, robust (controllers), with (shake table), & reduction of (structural responses) --> this type helps to highlight things for us to target or those that we have missed out, ignored or assumed
3. Specific contrary papers: these detailed papers have objectives that do not fit our objectives or needs, in fact can be totally opposite to our research --> e.g. Chase 2002 researches (semi-active control), using (semi-active dampers) & tries to diminish potential of active control (cost, power - nuclear plant (small one), complexity, design difficulty) --> this type helps us to see the inherent weakness of our side --> ideally, we should try to merge the strength of these into our designs

• Theorem of Least Work: always (not sometimes) do the least work to get done ... if it needs to be done in the 1st place ... never run 400m & come back sweating, but nothing done
• Principle of Priority: prioritize yr tasks ... some are definitely more needy & fundamental than others ... aim for the most basic ... an analogy is to fly needs to walk needs to move ... ensure can move first
• Doctrine of Stepping Stones: to get things done fully & completely ... all the inherent steps must be carried out ... identify all the necessary yet shortest (Theorem of Least Work) path of stones ... never try to skip stones (tasks) that are essential
• Way of fundamentals: anything we don't know, not sure or ignored ... are probably important ... when mistakes arise ... question the observed mistake ... then conduct a thorough revision of the fundamental trilogy --> Dynamics, Control, Optimisation ... this is the way of fundamentals
• TRIZ: we know monkeys can climb trees ... but TRIZ ... try this tried & tested methodology of problem solving: http://www.mazur.net/triz/ 

1^st Law of ReSearch

• General research papers
• Specific complementary papers
• Specific contrary papers

• Theorem of Least Work
• Principle of Priority
• Doctrine of Stepping Stones
• Way of fundamentals
• TRIZ

• Pyramid approach
• Inverted pyramid approach

Zeroth Law of ReSearch

• Open-loop control: internal dynamics are exactly, unambiguously known or measurable without delay ... then active control can be applied directly using these known dynamics ... then only open-loop or feedforward control is done ... if the system is only & truly governed by these known dynamics ... then there is perfect regulation ... i.e. error is zero ... all responses for all time is zero ... perfect controls
• Closed-loop control: when the internal dynamics (like variations in M,C,K) or external disturbances (like unknown EQ, noises, fluctuations, imperfections in understanding, modelling or construction) ... then open-loop control would be diastrous ... it would cause instability & collapse of structure ... hence, we need some form of self-correction & self-tuning within the controlled system ... here, we base the active controls only on the responses of the structure ... then apply a corrective control actions back into the structure ... to maintain equilibrium, achieve stability & reach desired responses ... this is the feedback or closed-loop control ... we feedback the controls into the structure to reach minimisation of responses
• Open-Closed-loop control: in the real-world engineering, dynamics of a structure is generally known (M,C,K) in some aspects & uncertain (dynamic variations in M,C,K & non-structural components) in others & totally unknown (EQ hazard analysis, catenary actions, collapse modes & mechanisms) in the rest ... hence, for known or measurable portions, use feedforward (FF) or open-loop controls ... for uncertain or unknown or unmeasurable portions, use feedback (FB) or closed-loop controls ... then, u(t) = FF(t) + FB(t) ... this is the most general form of active controls

• Knowledge: thought i know & have solved, but is based loosely on poor fundamentals
• Methodologies: thought i'm certain of the process & procedure, but is based loosely on some other techniques that in turn based loosely on others + some assumptions that tend to escape scrutiny ... this is similar to legal contracts ... clauses that are presumed & escape scrutiny that are important in some situations ... but not in others

Interim preparation

LQR 2/1/2003

7/1

8/1

I put forward this perspective to engineering (in every sense of the word) ... there are the following scenarios:

• Segregated, Theoretical Research: highly theory-based formulations, modelling ... yet largely neglecting the needs & wants of the present industry ... due to the following causes:
• Too futuristic (numerous assumptions) ...
• Too unrealistic (though theoretically feasible) ...
• Too unpractical (not directly applicable in the surroundings ... e.g. hot climate research cold climate stuff ... too costly ... too resource-consuming)
• Too complex: e fact that stds & codes are so prevalent in CE ... is evidence of the complexity & critical importance of CE structures ... there is an urgent need to simplify things ... using step-step methodologies or algorithms or procedures
• Too separated: though R&D is supposed to focused ... yet by the inverted pyramid approach ... we must relate back to the present conditions ... in direct & simple terms ... an Australian professor has commented ... "For the excellent expertise present in design & analysis in Singapore, it is unfortunate that it is limited in its execution. The actual construction capacity lacks far behind that of design" ... hence, our R&D is not being effectively disseminated & fused into the industry ...
• Segregated, Experimental Research: highly-specialised experimentation ... largely out of reach of the industry ... due to the same causes as above ... plus without proper communication (pyramid & inverted pyramid) ... all the sweat, toil & effort ... would exchange some virtual grade or paper or certification ... that e bosses would just flip thro' like newpapers ... let it be known that ... to be certificatied does not mean qualified ...
• Segregated, Theory-Experiment Research: a more complete form of R&D ... in that difficulties of both formulations & realisations are encountered & overcome ... yet without consideration of the industry ... would either result in:
• Exploitation by external parties: to strengthen their own fruitful R&D & industry causes ... might even be competitive with our own ... hence, form a vicious cycle ... causing thorough collapse of our own industry
• Admiration without Application: wow's aglore ... but eventually not implemented ... or even catch e attention of the users ... a tragedy ... like e Heros of e Marshes ... super-human efforts with misguided causes
• Integrated, Theory-Experiment-Industry Research: to address the shortcomings of the above segregated R&D ... we need to be aware of our present industry ... what it lacks & trends ... use Chinese saying: know yourself, know your environment ... have a good cause for e industry to guide the development of theory-experiment ... let not all efforts go into some hardbound papers & locked in some air-con rooms ... for integration, pay attention to the following:
• Thorough understanding of the industry: what it lags, needs
• R&D focus: what to target & how to popularise the fruits of R&D ... know e constraints & obstacles ... & work around them

• Kinesthetic: by action ... more of trail-error engineering ... self-observation & correction ... experienced-based ... analogy: bottom-up approach ... suitable for: complex situations, hence actions are simplified ...
• Logic-Evaluation: by thought ... more of science-based engineering ... knowledge learning & usage ... theoretical-based ... analogy: top-down approach ... suitable for: simplified (theoretical, assumed) situations, hence formulations & experimentations are complex & advanced ... yet what attracts people are not complexity (though society gives lots of praise) ... it is simplicity

i hope to highlight the importance of simplicity in such complex domain as ReSearch ... to ensure that people would be attracted to it ... & use it ... isn't that what research is for?

With actual, real physical phenomena --> mathematical modelling --> Uncertainties accumulate:

• Inherent uncertainties, errors: due to type of modelling used
• Cumulative uncertainties or errors: due to techniques used within modelling chosen

• Materials: behaviour
• Geometry: spatial
• Interactions: coupling between components
• Variations: dynamics of the above

• Exact: continuum mechanics ... continuous systems ... highly mathematical ... more science-based ... fundamental, but can be abstract (Lagrange, Hamilton, Newtonian, Galerkin) ... difficult to visualise & describe formulations ... but typically excellent results ... seldom used in stds & codes
• Approximate: some kind of idealisation ... with some assumptions (impt to note these always) ... can be unrealistic ... but still applicable to specific focus applications only ... need to minimise modelling errors to tend towards exact ... typically faster, simpler with varying results ... there are 2 types:
• Realistic formulation & effect: inspired by exact modelling ... but simplifed along e way for some kind of efficiency & simplicity ... like D'Alembert principle, Rayleigh-Ritz, FEM & their cousins
• Unrealistic formulation, but realistic effect: modelling representation not matter ... only ensure that the responses are good enough ... even faster & simpler ... like lumped-mass (non-consistent mass) with Maxwell element (lumped mass M, linear viscous dashpot C, linear spring stiffness K)

• Hence, our case ... only uses approximate ... with unrealistic formulation ... but simpler with good enough responses

9/1/03

Also ... note that those partition walls, utilitise, windows, doors, furniture ... have some effects on stiffness & less on inertia ... before they break, structure is slightly stiffer ... after they break, structure suddenly becomes weakened ... this comes as impact ... hence ... need to guard against this

12/1

Interim presentations 14/1

17/1

there is much confusion between which comes first ... chicken or egg? ... though this question is inconsequential to us civil engineers ... but we did encounter this dilemma in structural analysis ... which comes first ... force or displacement? ... i discovered that this question has been answered already ...

In structural analysis ...

Given: structural layout, material, geometry + loads (static/dynamic, point/distributed)

Response: 3 forms

• Primary (essential) responses: displacements, strains (& their derivatives: velocity (KE), acc (inertia), etc.)
• Secondary (natural) responses: forces, stresses (& their derivatives)
• Energy responses: various forms (but relative in nature (Einstein et al 1910)

• Strong form: exact, continuum mechanics (dynamics)
• Weak form: approximate, variational mechanics (dynamics), convergence towards exact @ infinitum
• Energy form: account for all work (internal + external)

• (1) + (3): virtual force assumed --> compatibility imposed: Force method
• (2) + (3): virtual displacement assumed --> equilibrium imposed: Displacement method (Stiffness method & D'Alembert are special applications)

• As for e chicken & egg ... leave it to e biologists

Thesis writing

following thesis points:

• Meaning of "Thesis": the word thesis means … the point that you are making … it's not no point or some blur corner in the bush … don't beat about the bush … in thesis, just go straight to the point … thesis writing is all about making that point (yr objective) only … in other words … yr niche

• Writing: report writing to us is quite common … but the difference is report is only for one particular tutorial scenario or one formula or one general topic … through yr Education … u must have met various forms of reports … some overview / survey: Literature review … some theoretical: Methodology … some testing/simulation/experiment: Results & Findings … even though a thesis has only one point … but its scope is larger … so thesis is like combining all the above types of reports … into one coherent, reasonable & logically-flowing argument … towards the point … writing then consists of 2 aspects: quality + quantity

• Quality aspect: the necessary condition … you pick out the main point … or theme & expand on it … essentially from thin-thick-thin … eventually, ensure that the reader gets what he wants … what u intend to do … what & how u did it … how it is applicable to him

• Quantitative aspect: the sufficient condition … length is strictly not a criteria … I have seen winning thesis of abt 60 pages only … & it is on wavelets in CE … I find that there are three types of scenarios here:

1. Brute force: settle down the thesis point & scope … expand freely regardless of length … unconstrained writing … normally very long … & very troublesome drafting & editing later on

2. Component-based: from objective & scope … divide-&-conquer … into smaller, simpler sub-objectives … write for each of these like a report, regardless of other sub-objectives … then combine them … then do overall editing to "tie the strings" so to speak

3. Coherent unity: write the thesis like single report … from the start to the finish … the writing & editing occur hand-in-hand … write one section … edit this section together with all previous ones … hence, write a little … edit the whole lot (to ensure coherence) … the writing part is not like brute force (without regards) or component-based (only for the sub-objective) … you are writing (as in every single word or symbol or character) for this current section … in order to reach the eventual objective (niche) … this takes practice … but if you try it now … the next time you do so would be easier

Component-based would be balanced between e two extremes … I would recommend this … but I must emphasize … eventually all of us would tend towards coherent unity

i like to point out 3 impt aspects:

• Equations: each equation line is preceded & postceded by a single spacing line ... equation itself is centred ... right margin has numbering sequence (Insert --> Field --> Numbering, Sequence)

• Tables: i recommend 1 page to have 2-3 tables max. ... each table abt 3 inches vertically (to fit into 9 inch page) ... each table must have a Caption (Insert Caption), centred & above the table

• Figures: i recommend 1 page to have 2 figures max ... each fig. abt 4-4.5 inches vertically ... each fig. must have a Caption (Insert Caption), centred & below fig.

Only when u mention any formula, table or diagram ... then u put it in ... never put it in without discussing it ... this goes for references also ... pls quote properly ... never use [1], [2] etc. ... use the name e.g. (Kamada et al 1998)

also text is double-spacing ... essentially, they r telling us to write as short as possible ... so we should not write too long-winded ... it saves paper, money, time & no wasted efforts (Theorem of Least Work) ...

oso ... never copy directly from others ... though an exception may be made for my drafts to u ... but they are only drafts ... use yr engineering judgement to write ... take it as a precious practice ... i don't believe we may get another such intense writing practice ever ... let's all treasure this most valuable experience

Below are a check of all necessary thesis components:

• Title: for thesis … as well as a shorter one to print along the stem of the thesis book during binding

• Abstract: the most important … the first to be inspected … all yr findings towards e niche thesis must be summarised here … if this is not written well … the rest would be ignored

• TOC: table of contents … nomenclature … tables … figures captions

• Introduction: general background … literature review (narrowing) … objective … scope (expand on objective, exactly what things to research on the objective) … layout (chap 2 what … chap 3 what)

• Body: summary sentence … problem definition / formulation … theory (equations) … methodology … verification/validation … tests … results (tables, figures) … findings: results with discussions back to the objective

• Conclusions: conclusions … back into objective … exactly what u find abt each scope component … successful, why & implications … fails, why & implications … suggestions for future studies (what u always to do but cannot)

• References

• Appendix: things like … program codes

Keep clear

Keep simple

Keep short

Stabilising energy

Engineering … whether physical or chemical or biological etc. … is essentially abt. E struggle between … capacity (good) … loads (bad) … there are then 2 scenarios:

• Capacity in equilibrium with loads: balanced thus no resultant forces/stresses … deformations/strains … energies (mechanical or chemical or otherwise) …

• Mismatch between Capacity & Loads: non-equilibrium … no balance yet … thus resultant exists … the effect of the existence of this resultant … is that disturbances & changes would occur … in search of balance … possible changes include changes in structure, load distributions & subsequent capacities … this induced change would always occur until the resultant is removed … i.e. balance is reached

Hence … engineering is our hand in … reaching & maintaining this balance of capacity & loads … N.B. it is best to have the highest capacity/loads ratio … but loads would always be there … the challenge to us is … the HOW we go about engineering this equilibrium or balance … yet … aiming equilibrium by itself is naïve … the reason: balance may be unstable … implication: need to understand stability concept … there are three equilibrium states:

• Unstable equilibrium: a false balanced state or state of balance … like an inverted pendulum … the exact point where the mass tip is exactly vertical is equilibrium … however, given just a slight perturbation laterally … the pendulum swings & leaves that equilibrium point permanently … hence unstable in that point

• Neutral equilibrium: a moving state of balance … like a ball … u roll it … it stops … that's the new balanced state … the equilibrium changes with each perturbation … but not really unstable in that it might come back to its original position … hence neutral

• Stable equilibrium: a true state of balance … like pendulum with mass tip at the bottom … like grandfather clock … push the mass … it swings … under damping … it stops eventually at the same downward position … hence, remains permanently in balanced position … thus, stable

In structural engineering … structures are supposed to be stable & not collapse (ULS)… in that they satisfy the 3S: stability, strength, stiffness … hence, an unstable structure would have the following:

• K<=0: no (neutral, critical stability) or negative (unstable) stiffness … in other words … instead of resistance to loads … it magnifies or provides zero resistance

• Internal structure: the internal organisation of the elements & members … & connections & braces etc. … are not able to transfer the loads to the supports … hence, they are either broken, hinged, missing or not arranged properly

• Supports yielding, failed, insufficient restraints: supports provides the anchors … the members are able to have induced forces/strains … is due to restraints … hence no restraints or insufficient ones … would violate stability … e.g. in-plane structure: 3 DOF supported

• Strain energy criterion: by COE … E=constant>0 … hence dE/dx=0 … but if E increases without bound i.e. endlessly increasing … & dE/dx>0 … then energy keeps adding up & little or no dissipation … with corresponding magnification of transmitted energy … then the structure would rock itself to death … essentially no internal structure without K & poor supports

In structural control … passive damping takes away inherent structure energy transmitted due to seismic loads … passive control shifts the fundamental freq. of structure away from EQ main peaks … semi-active control takes or dissipates structural energy by using ext. power to operate the dampers only … hence, it does not inject mechanical energy into the structure, it just takes away …

In active control … & composite or hybrid control … ext, power is used both for operating the active actuators … & also injecting mechanical energy into the structure … as evident from the energy balance equation … as active control is using (control) energy to reduce or cancel out (seismic structural) energy … remember energy is actually waves … & waves can be superimposed … irrespective of whether it is linear or nonlinear … thus waves can be cancelled … so can structural energy …

The problem … is that under arbitrary excitation like EQ … & unmodelled dynamics of the structure … & assumptions (all not true):

• Instantaneous with no time delay: from ground into structure, from sensor into D/A, from D/A to controller, from controller to D/A, from D/A to amplifier, from amplifier to actuator & from actuator back into structure

• Linear systems: no material (inelastic, hysteretic) nonlinearity or no geometric (2nd-order P-delta effects, induced M from out-of-plane bending) nonlinearities

• No corruptions: in measurements, perfect instant sensing & actuation

As engineers … we know that the no. 1 concept is that things would NEVER be perfect & would ALWAYS be imperfect … hence, our active control must be insensitive to all the above problems … one way is … to ensure that:

• Current E do not add up: i.e. they do not accumulate … i.e. E=const. & dE/dx=0

• Effective control: E is reduced or eliminated … i.e. E is dissipated or cancelled out by injecting stabilising mechanical energy … Et+1 << Et & dE/dt<<0 … best!

Here, E is the structural energy = SE + KE … only, so using the above criteria … CE must be able to achieve them … this concept is the Lyapunov 1st & 2nd methods … all energy-based methods that are equivalent in importance to Newton's Laws in mechanics

2, below is a paper on active control

… it also uses energy changes as stability analysis … get e concept of using energy changes as stability criterion (focus on paper Section 4) … eq (4.1) is similar to ours: SE+KE = IE-CE =E … by tracking this E … together with the proposed energy-based control (to oppose destabilising velocity only) … show that the controlled structure is stable … with criterion: dE<0 always … this can be done by … similarly splitting one oscillation cycle into stages … like e way u explain to me how it works:

• Each stage: show trajectory of tip mass … show whether control … control direction & magnitude
• dE at each stage: show that dE for every stage is … dE<0 always
• Inter-change of two adjacent stages: from one stage to another … e.g. from uncontrolled to controlled (due to destabilising velocity present) … also show that dE<0 …

Then … with this … infer that since the active control works in this way for every cycle … & that every cycle’s stages are all stable: dE<0 … therefore … dE<0 for all cycles … thus control stability is guaranteed … proved … then realise experimentally

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As engineers … we are often always called to tricky & sticky situations to resolve … & we are expected to resolve them completely … that's why the social sciences people label us as problem-solvers … pple problems … we solve … supposedly & completely … situations can be:

• Tricky: there are 2 aspects - obvious & hidden aspects … the obvious aspects are that can be immediately or almost immediately … observed & detected … the causes derived … the remedies must address both the problems & causes of those problems … the hidden aspects are the tricky parts … they are like time-bombs that await the ignorant engineer who thinks he has solved the obvious portions … which might be master-minded by the hidden aspects …

• Sticky: there are limits to the resources - tools, labour, expertise, time, etc. … that can be used … some problems are just too extensive, long-term & haphazard … sometimes here, other times there … there seems no apparent patterns or behaviour & no models & fundamental understanding to the phenomenon … these problems stick like mud … & the ignorant engineer who keeps the same techniques & methodologies against such problems … would find no progress in solution … due to resource constraints

Hence, we need to generalise our engineering approach towards tricky & sticky problems such that it can applied with confidence … independent of the problem domain …. Basically, this involves:

• Problem awareness: fundamental understanding of the problem … qualitative aspect: be able to conceptualise, simplify & reform into familiar & confident analogous problems … quantitative aspect: able to observe, detect & even model to support the qualitative aspect …

• Methodology: understand that e world system … as e problem system … is a dynamic & flexible one … in that … it can be altered & modified in such ways that can maximise the following … (Remedy effect) / (Constraints) ratio … the method must:

1. Amplify remedy effect: in our case … stabilise controlled structure … then, magnify active control efficiency & performance

2. Reduce constraints or restraints: reduce complexities, unknowns … by simplifications, verifications & re-configuring systems

Take the example of experiment set-up:

• What is the problem? Any hidden aspects?

• What are the resources (structure components, connections, sensors, controller, actuators & time left)? Have we utilised them all & to the maximum in the correct way?

• Have we amplified the control effects?

• Have we reduced the restraints that are confining our control effects?

Theory of Generalised Problem-Solving:

• Criteria: set a set of criteria or what we want to achieve by doing all these

• Problem understanding: awareness

• Selected solution: methodology to increase ratio of (remedy effects)/(constraints)

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10/3

In the niche perspective … each & every engineer has his own unique niche … or role to participant in … this niche has the following attributes:

• Uniqueness

• Individuality: specific to the individual engineer

• Dynamic: although unique, but not static … there is continuous variation of the niche … over time, space, context & circumstances (internal & external) depending on the system in question

• Fitness: to determine whether a niche fits an engineer … the engineer must try it … to see if it fits himself

To see fitness … focus on the interactions of the following:

• goods and bads

• up's & down's

• understand what we wish to do

• we can do

• we are willing to do

• the chances to do: opportunities … there are two aspects here … ????, ????

1. ???? Self-created: for situations that the engineer is comfortable, confident & experienced in … active sourcing for chances
2. ???? Open-hearted: the engineer understands the infinite complexity & uncontrollability of the reality … under the lack of infinite time & resources … with sometimes overwhelming constraints … that being active would only mean running 400m, come back sweating & absolutely nothing useful done … being active means being exhaustive … hence … the engineer settles down snugly into his routine niche … seemingly passive & retarded from the exterior … but … internally, the engineer is waiting … eagerly … the engineer knows circumstances are now greater than own capacity … hence, he waits … he goes into semi-active mode … being open-minded to all & every thing, man & methodology … he does not reject them due to past experiences … nor accepts them due to past knowledge … he attempts to reverse himself … to see the other sides of the problem … with open-hearted perspective

Our potential is measured by our fitness level … to reach our potential is good as reaching our niche … determined by the fitness … hence … our niche realization is equivalent to fitness … this consists of 2 chained processes:

1. Current niche: source for yr current engineering niche … focus on this niche, but maintain general relationships with peripheral issues … Jack of All, Master of One … & maintain this niche state … for as long as it is open for u
2. Niche transition: with the world affairs now … we can see clearly that the world is a crudely changing one … the only constant is change … people always hope some dream state to happen … but an engineer does not work with any unrealistic situation … hoping that a niche found would always statically be there for a person … is the worst engineering disaster … the ignorant engineer of course would choose to defend … but a true engineer would give up … & quietly move on … the transition of niche is equivalent to the hydraulics:

• Turbulent layer transition: an abrupt shift & change … where there are lots of changes, pains & agony … resulting large energy dissipation … what has been painstakingly built up over the previous niche … is now being eroded right in front of the eyes of the engineer … the engineer realises that he is not the king of his niche … but a lowly pawn of circumstances … the engineer needs to quickly internalise this state of affairs

• Laminar layer transition: a gradual shifting & changing … with internalisation of the current state … the engineer goes into niche-finding mode again … & flows along with the current … but not blindly passively following … only semi-actively waiting or creating for his new niche

• Wake transition: once bitten, twice shy … having encountered all this … & internalise it permanently … the engineer engages in his new niche with open-heart

Hence … what I like to conclude from this niche study are:

• Potential realisation theory: Niche-finding & fitness determination to reach our potential

• Niche transition: turbulent, laminar & wake layer transition phases … similar to what substances go through during processing

• Jack of All, Master of One: focus on yr current niche, but also cultivate various hobbies, likes & past-times … one day, they might come in handy … but never get distracted by them

• ????, ????: the engineer internalises this analogy … Subsystem à System à Suprasystem … for any one system that the engineer is currently focusing on … there is always a smaller, simpler & more fundamental subsystem below it … as well as … there is always a bigger, interactive & more complicated suprasystem above it … there are thus 3 states for any engineer:

1. System-level: maintain & train focus on the niche here
2. Subsystem-level: system too complicated … too many unknowns & assumptions … reduce to a more fundamental, simplified level … in energy terms … the engineer goes into a lower trophic level … from research … the lower trophic level, the more stable & comfortable it is … but people at higher trophic levels might despise u … choose to suit problem
3. Suprasystem-level: system does not provide sufficient insight … it is ok for some things … but is seriously lacking in others that the engineer is now interested in … hence the engineer groups, classifies, re-perceives & re-constructs from all other angles (Zeroth Law of ReSearch) … to uncover to discover the hidden interactions or misconceptions or illusions

There are two extreme levels to the potential realisation theory:

• Individual: to realise one's own niche potential, that is continuously varying with circumstances

• Macro-level: encompasses more than one individual … the aim is to realise the potentials of its members … e.g. our society … the authorities would shape & influence in such a way as to uncover sufficient niches of quality & depth … to ensure that its members (people & engineers) can find their way towards their niches … currently this level is too far-fetched for us students … but cultivate this as a part of Jack …

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In the potential realisation theory … we need to be aware of our niche … as determined by fitness … w.r.t. 謀事在人, 成事在天 … at any one time … we can be only in either of the 2 mutually exclusive scenarios … (1) within our niche … (2) niche transition: turbulent à laminar à wake … resulting in the rule-of-thumb: Jack-of-All, Master-of-One … this however is too loosely formed to be useful … hence an urgent need to reformulate this into a engineering niche for all ReSearch

With the presence of:

1st Law of ReSearch: feedforward open-loop generic technique … inherent in all operations

Zeroth Law of ReSearch: feedback closed-loop fundamental technique … inherent in all rectifications, awareness & understanding

Yet … all research tasks & events do not only involve the doing (operations, implementations) … & the corrections (realisations, fundamentals) … the events would ultimately involve concepts … yet no one can clearly define concept … as it is a virtual idea … with actual realisation or implementation … the concept influences the operations & understanding … the operations & understanding shapes the concept … hence there is always a closed-loop relationship between conception (virtual form) & concretion (actual form) … this is analogous to dreams & reality … how many realise our dreams, yet who can live without dreams? … to concrete is to cut off aspects of concept … to concept is to modify concrete … is there a dilemma or in engineering, a compromise/tradeoff between conception & concretion? … the solution or resolution is in the … interface … interaction … or architecture … of both elements of concept & concrete … yet interaction is still as undefinable as itself … to inter-act is to act in related fashion … with influences both within & without … both internally & externally … in other words, in dual mutually-exclusive extremes … the extremes in turn have their own respective extremes … forming infinitely-chained processes

hence, with this understanding (from Zeroth Law of ReSearch) of the influence of interaction on the balance between conception & concretion … the following 2nd Law of ReSearch is derived:

2nd Law of ReSearch states that all processes involve arbitrary chaining of the basic configuration of subsystem-system-suprasystem, with the system as the event-of-interest, where for any system, there would always exist a more fundamental, smaller, simpler, more rigid, less flexible, less powerful;, more stable & less interactive system – subsystem; and there would always exist a more complex, larger, less rigid, more flexible, more powerful, less stable but more interactive system – suprasystem.

Thus … with the subsystem-system-suprasystem basic form … any process can be potentially understood … if it is too complicated or illusionary … there can always be a simpler way to perceive, model & understand it … hence, when the engineer encounters a problem that is just overwhelming … the engineer does not dive into the concretion … the engineer falls back onto conception … with conception, the engineer interacts the relationship at levels that the engineer is fundamentally sound … & because there is always such a subsystem … the engineer can be assured of preventing progressive conceptual collapse, hence preventing actual concrete engineering disasters … potentially this means that all disasters can be avoided … if the 2nd Law of ReSearch can be internalised within the engineer … if only lay engineers can take tasks at their strides & capacities (know yourself)

Yet … there can be the opposite … now that the system is firmly supporting the engineer … the engineer engages in internalising the system to become routine … the act of routine is an act of future complacency … hence, the engineer moves into the suprasystem … to understand things that baffles him, that he has assumed, ignored, neglected, modified or given in the past … he needs new & extended insights into the process … hence, suprasystem is derived from Zeroth-Law of ReSearch … this can be from linear à nonlinear … from statics à dynamics … from elastic à inelastic etc. … because a suprasystem always exists … potentially this means that all & everything can be known & engineered … that there is always hope for engineering events … if the 2nd Law of ReSearch can be internalised within the engineer … if only lay engineers can internalise open-hearted spirit towards the surroundings (know adversary)

In summary … the 2nd Law of ReSearch is formed by the basic configuration of subsystem-system-suprasystem … where focusing on the system is the niche … focusing on the subsystem is the careful, pre-emptive protective stabilising approach … focusing on the suprasystem is the hopeful energising exciting vigilant approach… hence, a rule-of-thumb is:

If it is too difficult, go easy

If it is too easy, go difficult

Eventually … provided inherent damping exists … the mutually cyclic shifting between the extremes would settle at hopefully a stable equilibrium position … but life (not to say engineering) is an unstable phenomenon … hence the following trends:

• Simple things would always complicate over time & circumstances

• Complicated things would always simplify over time & circumstances

• Oscillations always exist between the shifting extremes of simplicity & complexity

I’m not sure where this would lead to … but neither does the engineer … hence, the engineer does not argument or debate or probe into issues of such nature … as the engineer knows that he should only focus & focus only on his niche … & little else … hence, with this … I like to end this prolonged annual research into the basics of research with u … thank you for yr attention …

May the Engineer be with You