Programmable Architecture
-Towards Human Interactive, Cybernetic Architecture-

Kensuke Hotta (B.Eng, M.Eng, Msc),
Architectural Association School of Architecture

プログラマブル アーキテクチャ


堀田憲祐, 英国建築協会建築学校 

Chapter 5 Data and Analytical Methods

第5章 データおよび分析方法

5-1. Evaluating Performance in Adaptive System

While chapter 4 elaborates on the proposal of PA architecture with its physical and construction models as well as multiple hierarchies, chapter 5 addresses the issue of how to quantify this new kind of relationship with the environment focusing mainly on light levels.

第5章, データおよび分析方法 


     The proposed approach involves, first, performing some baseline case studies. These are correlated using a software interface which ‘metabolises’ the results. This ability will lead to various applications executable from a small architecture scale up to larger urban patches with multiple intelligent units. After the software is ‘trained’, it should be evaluated in a functional environment since it may not always know how to respond usefully to its complex real-world environment. This PA will be evaluated to see how it can work effectively for human society and the environment.


     If architecture is genuinely ‘programmable’, its metabolic interface can be adjusted based on the results of the ongoing evaluative process. Moreover, as the software is ‘intelligent’, it will have a self-developed system such as a neural network. When the system works well, it should be able to record its history of ‘training’ and ‘learning’ and prove that it is possible to create adaptive software metabolisms without any change to the hardware.


5-2. Details of Methodology in Previous Experiments

5-2. 先立つ実験の手法の詳細

Before this thesis, the author proposed the concept of “Programmable-Kinetic-Fabric for Architecture'' at the Bartlett in the university college London (Hotta,K 2009). master’s degree thesis, in which several methods were utilised to control architectural machines. Three types of architecture were identified in an experiment that focused on active light shading to develop kinetic architecture. In addition, several tools were used in the experiment, particularly Arduino (hardware) and the Genetic Algorithm (software). This case study is related to both hardware and software systems. (fig 5-2,1)


     Two key challenges, as well as potential, came out of this project. The first challenge (potential) was the hardware; architectural hardware should be capable of receiving a signal and acting accordingly. If we look at cars or any other intelligent object, we can easily find that some systems can change morphologically and functionally. Another challenge (potential) was the software; no single software system can control all aspects of an architecture system. The exceptions to this rule would be an environmental or energy management system, but this is only a part of complex architectural equipment.


Fig.5-2,1: Illumination Experiment, on the thesis at UCL (by Author and A.Hotta, 2008 ) 
図.5-2,1: UCLでの照明実験の様子(筆者+A.Hotta, 2008年) 

5-3. Initial Physical Study 

5-3. 初期物理モデルスタディー 

5-3-1. A Building Envelop Experiment

During the 2010~2011 period, several experiments were performed. The first experiment involved comparing the amount of sunlight within different building envelopes containing the same footprint controlled by a ‘Selfish System’ or a ‘Concession System’. The Selfish System’s control principle is that each envelope object tries to get maximum sunlight without considering others. In contrast, the Concession System‘s control principle is that each envelope is allowed to work as part of a group cooperating for group efficiency.

5-3-1. ビルディング・エンベロープの実験


Fig.5-3-1,1: Building Envelope Experiment: Setup (by Author)The Rope on the diagram shows the outline of the building, called the ‘envelope’. The footprint is fixed at the lowest point with pins. The rope (envelope) can move and change its shape. The pin in the middle of the string represents the light detector. The detector’s efficiency depends on the angle towards the sun’s rays at that point.
図.5-3-1,1: エンベロープ実験の前提条件等セットアップ (筆者)図中のロープは建物の輪郭を示しており、ここでは「エンベロープ」と呼ばれる。足元はピンで固定されている。この制約中でロープは自由に動き、形を変えることができる。ロープの中央にあるピンは、光検出器を表している。検出器の効率は、光源(太陽)に対する角度によって変わる。光量の計算は、ロープのその点での太陽の光の垂直からの角度の関数(コサイン)で算出される。

     The experimental results indicated that the ‘Concession System‘ got a higher score (1190 points) than the ‘Selfish System’ (1003 points)(fig 5-3-1,3)(fig 5-3-1,4). This means if an urban patch, the Urban patch is a technical term for a section of a town block, operates using the Concession System, it can achieve higher efficiency. Based on these results a number of issues were identified for further development. Firstly the precise logic of the ‘concession’ used to achieve a higher score needs to be precisely defined; secondly the issue of a central or distributed control system needs to be addressed and finally the location and nature of the evaluator need to be addressed (the score was calculated by hand in the experiment).


Fig.5-3-1,2: Building Envelope Experiment, Initial Situation (by Auther)There are three envelopes in this experimental field (urban patch). The light source comes from the upper right position making shadows on the opposite side. Calculating illumination at the various points is the same as in the previous diagram. The actual functions are shown below.
図.5-3-1,2: ビルディングエンヴェロープの実験、初期状態 (筆者)この実験都市区域(アーバンパッチ)には、3つの建築物とそのエンベロープがある。光源は右上の位置からきており、反対側に影をつくっている。各点での照度の計算方法は、前の図と同じである。実際の関数は以下の通り。

Amount of Sunlight building1

= Σ {(S1-1)+(S1-2)+(S1-3)}

= Σ {(x*cos0°)+(x*cos(-50°))+(x*cos(-89)°)}

Amount of Sunlight building2

= Σ {(S2-1)+(S2-2)+....(S2-13)}

= Σ {(x*cos62 °)+(x*cos53 °)+(x*cos60 °)+(x*cos53 °)+(x*cos34 °)+(x*cos11 °)+(x*cos(-48

°))+(x*cos(-86 °)+(x*cos(-119°)}

Amount of Sunlight building3

= Σ {(S3-1)+(S3-2).....+(S3-8)}

= Σ {(x*cos0°)+(x*cos(-50°))+(x*cos(-89)°)}

The total score of this field (Urban patch) is simply the sum of these 3 scores.


Fig.5-3-1,3: Building Envelope Experiment: Selfish EnvelopesThe total score was 1003 points (Building1: 250points; Building 2: 700 points; Building3: 53 points)
図.5-3-1,3: ビルディング・エンベロープの実験:利己的なエンベロープ合計1003点(建物1E:250点、建物2E:700点、建物3E:53点)。
Fig.5-3-1,4: Building Envelope Experiment: Concession EnvelopesThe total score was 1190 points (Building1: 200points; Building 2: 680 points; Building3: 310 points)

     For these questions, it is worth referring to animal physiology, especially the reflex system. (fig 5-3-3) Humans have two different reflexes - spinal reflexes which are autonomic, and cerebrum-based reflexes which are more intelligent and voluntary reflexes from within the brain. Both have their merits, the first providing speedy reactions, the second providing ‘smart’ reactions. Animal sensing systems use a combination of local reflexes and central reflexes to achieve dynamic reactions. How might this work in a machine system?


Fig.5-3-1:5: Hybrid Reflex System drawn by Author, Referring from Dr Joseph Mcnairm, MDC
図.5-3-1,5: ハイブリッド・反射・システム図:(筆者作、ジョセフ マクネアー博士、MDCを参考)

5-3-2. Kinetic Robot Studies

The second experiment, which was carried out used a different reflex system based on the hypothesis that the combination of different reflexes would result in more light in the experimental space and thus achieve higher scores. The objective of this experiment was the same as the above where building envelopes change their shape to maximize the amount of sunlight using real-time sensing. There were two models used, each having different control principles. One is an electric-based centrally controlled system, where the central reflex is a coded reaction using electrical signals (fig 5-3-4). The other is a material-based, distributed system, where the distributed-local reflex is material-based using Bio-metal(R), which is a type of shape memory alloy (fig 5-3-5). These robotic structures were operational.

5-3-2. キネティックロボット・試作


Fig.5-3-2,1: Trial Machine 1_ Servo Envelop Robot (Component Distributed type)Those are screenshots from the video of the experiment. The machine is controlled using an Arduino, light-responsive sensors and servos, and has three sets of them attached to a flexible envelope (a strip of soft structure, like the outer covering of a building). These servos are connected to the envelope by threads, so that when the sensor detects light, the entire envelope changes shape in real-time, after which it returns to its original shape due to the elasticity of the material. The control system is a distributed type consisting of a component made up of a set of servos and a sensor, though it is physically centred type by one microcontroller. It can also be fully component-autonomous and fully decentralised if the microcontroller has the right number of actuators.
図.5-3-2,1: 試作ロボット1_サーボ・エンベロープ・ロボット (コンポネント分散タイプ)これらの画像は実験のビデオからのスクリーンショットである。この機械は、マイコンArduinoと、光に反応するをセンサ、サーボ使って制御されており、柔軟なエンヴェロープ(帯状の柔らかいストラクチャ、建物の外側の被膜のようなものを想定)にそれらが、3セット取り付けられている。これらのサーボはエンヴェロープに糸でつながっているため、センサーが光を感知するとリアルタイムでエンベロープ全体の形が変わり、その後は素材の弾性で元の形状に戻る。物理的には1つのマイコンに集約されているが、制御系はサーボとセンサが組で構成されたコンポーネントでコードも分散型といえる。マイコンをアクチュエイターの数揃えれば、完全なコンポーネント自律型の完全分散型にもできる。
Fig.5-3-2, 2: Trial Machine2_Tensegrity Arch (Material-based distributed system)Screenshots from the video of the experiment. The model is made with bamboo lodes (brown), elastic strings (red), and shape memory alloy (Thin black wire). When a heat source heats the shape memory alloy part, a hairdryer, the relevant part of the structure gradually begins to change shape and the deformation is soon transmitted to the whole structure. This system is a material-based responsive system so there is no central brain (processor).
図.5-3-2, 2 : 試作ロボット2_テンセグリティ・アーチ(材料系応答システム)この写真は実験ビデオからのスクリーンショットである。竹で作られたロッド(茶色)、ゴム紐(赤色)、形状記憶合金(細い黒線)で構成されている。熱源であるドライヤーで形状記憶合金部分を温めると、構造物の該当部分が徐々に形状を変え始め、じきにその変形は全体に伝わる。このシステムは物質による応答システムのため、中央の脳(プロセッサー)はない。

5-4. What is Going to Be Examined

The term 'programmable' in this paper means that the required built environment, which is tied in advance to a building function (programme), can be made variable and respond to human activity at any given time. In this experiment, illumination levels were used to evaluate the architecture, in particular the roof’s adaptability to varying levels of illumination. This particular value was chosen as optimum illumination levels have already been established in many environmental institutes, such as IES; Illuminating Engineering Society of North America, MS1525; Malaysian standard, or Panduan Teknik JKR or JISZ9110; Japan industrial Standard. Here, IES’s standard illumination level is used for the setup.

5-4. 何を検証するのか

 本論文でいう「プログラマブル」という言葉は、あらかじめ建築機能(プログラム)と紐づけられた要求建築環境を、可変にし、その時々の人間活動に対応できることを意味する。この実験では、建築物の性能を測るために照度が用いられ、特に下部空間での必要照度への合致度を評価軸とした。室における必要照度の特定の値はすでに、各国の建築環境系の学会や団体で設定されている。例えば北米照明学会の(IES)、マレーシア規格MS1525(Panduan Teknik JKR)、や日本工業規格の(JISZ9110)などである。ここでは世界的に普及しているIESの標準的な照明レベルを使用した。

     Since there is no established index to show the level of adaptability of a structure to environmental changes, the author attempted to develop a process for measuring ‘correspondence to the required environment’, which would identify the extent to which an architectural machine can follow its target or ‘objective’ function when dealing with the environmental change around the machine (Fig.5-4,1). 


Fig.5-4,1:The Gist of Experiment 
図.5-4,1: 実験の趣旨

5-5. Examine, Evaluate and Compare a Fixed and Kinetic Roof

The diagram below (fig.5-5,1) (fig.5-5,2) shows the method, which compares the performance of a fixed roof and a kinetic roof in terms of illumination performance. The two columns on the left show the relationships between an activity, a room or space and its required illumination level based on the IES-The Illuminating Engineering Society of North America-which is the recognized technical authority on illumination. The red line shows the available environmental (solar) illumination over 24 hours referred to as the Sun Light, SL(t), while the black line shows the necessary levels of light within the structure over 24 hours referred to here as the Objective Function, OF(t). On top of this the performance of the Fixed Roof, FR(t), and the Kinetic Roof, KR(t) are overlaid. This is a figure of wishful thinking, but if this is shown in an experiment, then the kinetic roof closely matches the objective function over the 24-hour period and is, therefore, more efficient and thus is able to encourage specific activities with more accurate amounts of light, than the fixed roof.

5-5. 固定式屋根と可動式屋根の検討、評価と比較


Fig.5-5-1: The relation between room illumination level and architectural functions (Auther referring to IES)The graph indicates the correspondence between illumination level and Activity, and also Activity and Architectural functions. The data is referred from IES; the Illuminating Engineering Society of North America. (
図.5-5-1: 室内照度と建築機能の関係 (筆者,参考IES)このグラフは、照度と人間の活動、またそれと建築機能との対応を示している。データはIES(北米照明学会)から引用。(
Fig.5-5-2: The Estimated relation between required room illumination level, and time-based architectural performance (Auther).The graph indicates the estimated result that corresponds between the required illumination level for certain architectural functions and architectural performance as illumination level. The black line shows the required illumination level (=objective function), the Blue line shows the estimated illumination level (architectural performance) under a fixed roof, and lastly, the Green line shows it as well but under a kinetic roof. The coloured hatches (S0, S1, S2) show the difference between the objective function and estimated performance on each, it indicates the performance of each roof. Smaller is better here.
図.5-5-2: 室内照度要求値と時間軸のなかでの建築性能の関係推定(筆者)このグラフは、ある建築機能に対する必要な照度レベルと、実測の照度レベルとの対応関係を、推定した結果を示している。黒い線は必要照度(即ち、目的関数)、青い線は固定式屋根の下での推定照度(即ち、建築性能)、最後の緑の線は可動式屋根の下での推定照度を示す。カラーハッチ(S0,S1,S2)は、それぞれの屋根における目的関数と推定性能の差を示しており、各屋根の性能を示している。ここでは小さい方が良いとされる。

     Here sunlight refers to all sky illumination. These values are set on the assumption that the place is Japan in the summer and the weather is fine. The maximum illumination level might be 100,000 (lx) at peak time, which is generally around noon.

SL(t); Sun Ligh  (Japan, Summer, Fine)


SL(t); 太陽の光  (日本,夏,晴れ)

Fig.5-5-3: Sun Illumination, representative day and time (Auther) 
図.5-5-3: 太陽光の照度、代表的な日時 (筆者) 

• Objective function

The objective function is to set the Required Illumination level for activities for an arbitrarily chosen normal office worker. This line is just one possible example. Of course, a person’s behaviour is unpredictable and their required illumination level fluctuates along the timeline. It is not so easy to predict what will happen in the real world.

OF(t); Objective Function (Required Illumination level for activities)



OF(t); 目的関数 (活動に必要な照度レベル)

 • Approximate illuminance of the space below, provided by the individual roofs

On the graph, these lines are shown as the green line (FR(t); Fixed Roof ) which is the Illuminance values in the lower space provided by a conventional fixed flat roof. The blue line (KR(t); Kinetic Roof ) is the dynamic roof proposed in this thesis.  Values and lines shown on the graph are provisional, calculated values. After the experiment is completed, these can be replaced with the experimental values. 

KR(t); Illuminance Provided by a Kinetic Roof

FR(t); Illuminance Provided by a Fixed Roof


グラフ上では、従来型の固定式フラットルーフ屋根によってもたらされる下部空間の照度値を緑線(FR(t); Fixed Roof )、本論文で提案する可動式屋根によってもたらされるそれを青線(KR(t); Kinetic Roof )で示している。グラフに表示されている値や線は、暫定的な計算値である。実験終了後、実験値に置き換えることができる。

KR(t); 可動式屋根によってもたらされる照度

FR(t); 固定式屋根によってもたらされる照度

• The Remainder Areas as error; S

Essentially the Kinetic Roof (fabric) tries to follow the Objective function, that is it tries to minimize the difference between Objective Function and the values from the sensors on the roof. In this graph, the difference between the Fixed Roof and Objective Function is indicated by the ‘S1’ area. The ‘S2’ area is the difference between the Kinetic Roof and Objective Function. Although in actual time it is the sum of the differences, geometrically both S1 and S2 can be calculated using curve integrals along the time axis (t) on the graph.



Fig.5-5-4: The diagram of remainder areas as error; S (Auther) 
図.5-5-4: 差分としての残り領域; Sの模式図 (筆者) 

• Logarithmic calculations

     The logarithm calculation is useful when the values are not easily comparable and where the area (s) potentially has no limit with the possibility of the value diverging to infinity.

The resulting calculations yielded an S1 value of 46 and an S2 of 30. These values were calculated using a logarithm based 1.01. 



  Fig.5-5-5:  Logarithmic calculations and the index (Auther)
  図,5-5-5: 対数計算と指標 (著者) 

Defined Indicator

     The indicator presented here shows how well the actual measured values correspond to the required illuminance level, which is the objective function. Using the logarithmic calculations the correspondence to the required levels of illumination of the Objective Function is measured using new indicators (x; x1, x2). This indicator’s (x’s) range is from 0 to 1 where 1 represents absolute correspondence to the required light levels. For the value to approach 1 there is less tolerance for error, in other words, this roof system must follow the Objective Function. 


 ここで示される指標は、実測値が、目的関数である必要な照度レベルへどのくらい対応しているかを現わすもの。上記の対数計算などを駆使して、指標(x; x1、x2)を使って表現する。この指標(x)の範囲は0~1までで、1が要求される光量に対する絶対的な対応であることを表す。この値が1に近づくほど誤差がないことを意味する。言い換えれば、この屋根システムはより正確に目的照度を満たし続けていることになる。

・Demonstration results.

     The 'required environmental response index' for the movable roof is x2 = 0.76, whereas that for the fixed roof is x1 = 0.66. This indicates that the movable roof fulfils the required function of lighting in the building plan more efficiently over the time span. Moreover, if the movable roof has an autonomous correction function as well as reflection, it would be able to adapt to longer periods of time and under different weather conditions.



5-6. What is the Contribution

With the development of ‘smart’ and’ metabolic’ systems like kinetic structures, they needed a new way of evaluating their conditions as well as a way of being assessed. Developing the ‘correspondence to required environment’ index provides a way of doing this. Other researchers could expand this index to cover a wide range of environmental factors. As the proposed architectural machine took a higher score in this indicator, the system has more resistance against the environment, thus making it more adaptable to a broader range of conditions. When the roof system is applied to extreme climatic zones such as hot deserts, or the frigid Arctic, it will work more effectively to maintain the required inner conditions.

5-6. ここでの貢献とは


Fig.5 5-6: Sun Illumination (K.Hotta)
The left hand diagram shows high time-responsiveness, which means the output function quickly constricts to match the objective function. The right hand diagram has a lower time-responsiveness. The system takes time to reduce the difference between actual output and objective function.
図.5-6,1: システム性能の推定 (K.堀田)

     System will adapt the output following the objective function. So the system can be judged the difference between objective function and actual output function. But also system can be evaluated with time. Dynamic system is laid on the timeline, so the adaptability can also be shown like the diagram. In the idea of homeostasis, the quicker response is the better. However the adaptability (=the difference between objective function and system output ) in the certain time duration, are not always correspondance with time-responsiveness. Because high convergence will bring smarter answers in the stable objective function, on the other hand it could be a lack of adaptability in the case the objective function is fluctuating.