The Use of Computer Simulation Program in Urban and Architectural Research

Simulation is a method to describe a system by developing a model of the system and perform a series of trials to estimate the behavior of the system at a certain time. Simulation method is done if the field observation of the research object is not possible. Simulation method does not yield a way to solve the problem directly but only evaluate a few alternative solutions to solving the problem. Along with the development of computer technology, the simulation method also uses computer technology primarily to help calculate a mathematical model. Some researchers in the field urban and architectural research has used simulation methods to solve the existing problems. This is because the object is an object of architecture and urban are very large and complex that it is impossible to conduct an experimental modification to the object of study. Some researchers are using computer simulation method is Satwiko (1998), Jesionek and Bruse (2003), Shasua-Bar, et al (2005), Kusumawanto (2007), Nugroho (2007), and much more.

Groat and Wang, 2002 reminds some factors to be considered in the simulation are:

- Accuracy of the model

- Completeness of data input

- The resemblance to reality

- The cost and workability

Various programs have created a computer simulation model to assist with the research theme of the relationship between architecture / urban micro-climate conditions. The basis of calculations used by the simulation model program were from the empirical, as CTTC Model (Shasua-Bar, Hoffman, 2000) as well as numerical or mathematical calculations, such as CFD, etc. ENVImet. While there is scope in terms of the nature of 2D and 3D. ENVImet is one program that is a 3D simulation.

Hot Humid Tropic Urban Climate Characteristic

For the purposes of architecture and urban planning and design, climate as most appropriate classification is based on considerations of human comfort (Szokolay, 1979). Based on these considerations, the climate is divided into;

• Climate (cold climates) where the main problem is the lack of hot almost all year round. Area with this climate lies in the polar regions.
• Moderate climate (moderate climates), where there is seasonal variation between the time when the excessive heat (overheating) and the lack of heat (underheating).
• The hot dry climate (hot dry climates), where there is excessive heat (overheating), but dry air
• Warm, humid climate (warm humid climates), where the main problem is excessive heat (overheating) and high humidity.

Tropical region is a region that lies between the Tropic of Cancer (23.5 ° N) and the Tropic of Capricorn (23.5 ° S). In regard to the climate, the "tropical" is an area located between 20 ° C isotherm line in the northern and southern hemisphere. (Lipsmeier, 1994). Tropical climate is divided into 2 (two) major climatic regions, namely the tropical humid and dry tropics.

Solar radiation is the main factor of all the general features of climate (Lipsmeier, 1994). Areas with a humid tropical climate receives average solar radiation - the daily average larger than other regions. This causes the humid tropics have different average temperature - the average annual low (2-3 ° C) while the average temperature difference - average daily high (8-9 ° C). Highest temperature reached about - about two hours after noon, because at that time joined the direct solar radiation and the temperature is already high.

The amount of solar radiation also causes evaporation of water so the moisture in the humid tropics is higher. The higher the temperature the greater the water vapor that can be conceived to approach the saturation point.

Urban Open Space Typology

Open space in a city is part of the urban space. In general, a typology of open space can be grouped into
- Geometric shape (Zucker, 1973; Krier, 1979; Moughtin, 1992)
- Function (Krier, 1979; Moughtin, 1992)
- Characters (Car, 1992)
- Degree ketertutupannya (Spreiregen, 1965)

Geometric form of urban open space is divided into two groups: square and street (Krier, 1979; Moughtin, 1992). Square is a form of urban open space that is static, such as squares, playing fields and city parks that usually are centered and inward looking. While the street is dynamic, linear oriented at both ends, such as roads, pedestrian paths and so on.

The basic square shape according to Krier, 1979, derived from basic geometric shapes are triangles, rectangles and circles. Modification of the form - the basic form is a concern with the technique of angled space, segment of the basic element, overlapping / merged, adding to and distortion.

Physical quality of urban open space is determined by the degree ketertutupannya / enclosurenya level (Moughtin, 1992). This degree of closure will affect the meaning of a place. Degree of closure is determined by the ratio of the height (H) around the building and the wide open spaces (D) of the open space. Quality enclosure according Spreiregen, 1965, namely:
- H: D  < 45: full enclosure
- H: D <30: treshold enclosure
- H: D <18: keterlingkupan minimum enclosure
- H: D <14: loss of enclosure