Subdivision Design Research Articles

Low Impact Development Applied to Teaching Architecture and Urbanism: Study of An Urban Subdivision

Objective: This work presents an experience of applying LID – Low Impact Development – ​​concepts in teaching architecture and urbanism. Theoretical Framework: The theoretical framework of the work was based on materials related to more sustainable urban drainage techniques and urban design, as well as on works aimed at teaching architecture and urban planning and referring to the profession of Architect and Urban Planner. Method: The methodology used in the article was defined in five stages: definition of the main bibliographic references; choice of area for implementing the study; demarcation of the watershed area and calculation estimates of the impermeable areas and contribution area for surface runoff in the pre-occupation scenario; development of the land subdivision design; calculation of the post-occupancy scenario. Results and Discussion: The work discusses a residential subdivision project, exploring the incorporation of issues related to rainwater management. The results show that the student's mastery of topography and hydrology concepts can help in understanding the morphological characteristics of the location of the proposed project and, above all, the conditions of the watershed. Research Implications: The inclusion of bibliographical references on LID, cartography and hydrology in the syllabuses of Architecture and Urban Planning courses is of fundamental importance, as well as the development of integration methodologies between the subjects of such disciplines. Originality/Value: The study can help future professionals to be more capable of dealing with the demands for technical solutions arising from climate change and the complexity inherent to urban planning.

Developing a Bi-Level Optimization Model for the Coupled Street Network and Land Subdivision Design Problem with Various Lot Areas in Irregular Blocks

Street design and land subdivision are significant tasks in the development and redevelopment planning process. Optimizing street and land subdivision layouts within a unified framework to achieve solutions that meet a set of objectives and constraints (e.g., minimizing parcel area deviation from standard values, minimizing land consumption for street construction, etc.) is a critical concern for planners, particularly in complex contexts such as blocks with irregular shapes and parcels of varying sizes and requirements. To address this challenge, a mathematical formulation is presented for the bi-level street network and land subdivision optimization problem. Subsequently, the solution procedure is outlined, which utilizes a genetic-based algorithm for street design and a memetic–genetic-based algorithm for land subdivision. Finally, two cases are presented, solved, and discussed to analyze and verify the proposed mathematical model and solution procedures. The results suggest that the formulated problem is suitable for addressing the coupled street network and land subdivision design problem, and it can be adapted and extended to other case studies. Additionally, the introduced ideas and algorithms satisfactorily solved the stated problem.

Experimental study on the air cushion effect during the flooding process of a damaged ship cabin

In the rapid flooding process of a damaged ship, the air trapped in a damaged cabin will be compressed into an air cushion, which causes the air cushion effect (ACE). The ACE has a significant influence on the flooding process of an airtight cabin. In this paper, a three-cabin model is designed according to a parent ship, and a series of model experiments are carried out. First, the air-tightness ratio is defined by combining various air vents with different opening areas, and the flooding model experiments of different air-tightness ratios are carried out. The heeling and trimming angles of the model, the overpressure of the air cushion, and the water height inside the flooding cabin are recorded and analyzed, and the characteristics of ACE are summarized. Second, different forms of air vents with a same air-tightness ratio are designed, and the influence of the air vent distribution on the flooding process is analyzed. With the quasi-static method used for comparisons, the numerical results are compared with the experimental ones to check the effectiveness of the quasi-static method on the rapid flooding problems. The research on ACE can guide the design of ship subdivisions and provide a reference for the rescue of shipwreck accidents.

Parameter space exploration for the probabilistic damage stability method for dry cargo ships

The prediction of the statutory attained subdivision index is a challenging issue for the initial design of ships due to the design freedom offered by a probabilistic damage stability assessment. To this end, optimisation techniques integrated with a parametric model of the internal layout may generate a preliminary subdivision design, fulfilling damage stability regulations and cargo volume requirements. The present study explores using a multi-objective constrained optimisation algorithm coupled with a parametric model of a single hold cargo vessel, first investigating two design goal alternatives and secondly performing a global sensitivity analysis on the design variables for the most promising solution. The adoption, in parallel, of state-of-the-art practices shows the validity of the obtained solutions and the time benefits for designers. Nonetheless, the non-linear nature of probabilistic damage stability does not allow for clearly identifying the most impactful parameters on the attained survivability index.

Development of 0.34 THz Sub-Harmonic Mixer Combining Two-Stage Reduced Matching Technology with an Improved Active Circuit Model

In this paper, a high-performance 0.34 THz sub-harmonic mixer combining two-stage reduced matching technology with an improved active circuit model is established and analyzed. The mixer’s improved active circuit model is realized by decomposing passive functional models into basic transmission line units and their impedance matching and filtering are realized through automatic optimization. The improved active circuit model takes out the RF (radio frequency) transition model separately to set an optimization goal instead of operating directly in the mixing circuit. Compared with traditional active circuit models in the SDM (subdivision design method) and GDM (global design method), it provides a massive optimization space, larger working bandwidth, and better results. In the RF frequency range of 320–360 GHz, the SSB (single sideband) conversion loss of the 0.34 THz sub-harmonic mixer is below 9.5 dB and the RF return loss is less than 12 dB.

The Development of Frequency Multipliers for Terahertz Remote Sensing System

This paper summarizes the development of novel Schottky-diode-based terahertz frequency multipliers. The basic structure and manufacturing process of planar Schottky barrier diodes (SBDs) are reviewed, along with other diode structures that have been proposed in the literature. A numerical modeling method for the novel diodes in the context of terahertz frequency multipliers is presented, which includes 3D electromagnetic (EM) modeling, electro-thermal modeling and modeling of physical non-ideal effects. Furthermore, a general design methodology for developing terahertz frequency multipliers is introduced, involving a sub-division design method (SDM), a global design method (GDM) and a half-sub-division and half-global design method (HS-HGDM). These methods are summarized and compared for 110 GHz and 220 GHz frequency multipliers in the context of communication and imaging applications. Laboratory measurements of these multipliers show good agreement with numerical simulations. Finally, several classic terahertz remote sensing systems are reviewed, and a 220 GHz remote sensing system established using novel frequency multipliers for security inspection purposes is presented along with associated imaging results.

Diagrammatic information and environmental parameters: decision making in the early design phases

In the last decades, the initial phase of the design process has been discussed from the point of view of the construction process economy contribution. In this sense, several authors highlight the decisions made at this stage as an impacting point of influence on the direct cost of the building. This concern is repeated in the cases investigated by the ZEMCH (Zero Energy Mass Custom Homes) group in Brazil, which is focused on social housing, consequently, cost becomes a fundamental factor that must be considered on these buildings’ life cycle. Furthermore, ZEMCH’s workshops in Brazil have characterized the initial phase of the design process as a process that requires speed and simultaneous control of a large amount of data by the designers. Over these perspectives, the objective of this work in progress is to verify the potential of a diagrammatic artifact as an intuitive tool of visualizing information and supporting decision making in the initial phase of the urban land subdivision design process, to obtain energy efficiency during the building’s life cycle. Therefore, diagramming information of the environmental conditions into a visualization tool, helps designers to deal with requirements of this phase and cause impact on the operational cost of the building. This research was conducted over the Design Science Research method, and concludes that although visualizing information with the aid of an artifact can play an important role for the practical requirements of the early design phases, the solution can be potentially expanded to other purposes such as teaching, and even for users self-awareness on the operational impact.

QUANTIFYING THE IMPACT OF URBAN INFILL ON THE URBAN HEAT ISLAND EFFECT – A CASE STUDY FOR AN ALTERNATIVE MEDIUM DENSITY MODEL

Abstract. Urban Heat Islands (UHIs) impact the quality of life in many urban centres. Metropolitan areas of Australian cities and urbanised regional centres, in particular, show vulnerability towards UHIs due to challenging climatic conditions and the model of greater subdivision of established properties whereby backyards and mature trees are replaced with more residential dwellings and sealed areas. The measurements for the UHI mitigation, such as imposing reforestation, employing sustainable and medium density housing build form typology must be quantified. Simulation-based identification and mitigation of UHIs can be used for planning decisions. There are several advantages to use simulations. For instance, alternative subdivision design, building design and the placement of trees and other measures is only required in the digital twin. Experimenting with the digital twin saves resources and maximises the outcome by being able to quantify the heat reduction. The aim of this work is to quantify the impact of the current urban infill methods on UHI. We focus on an area that has gone through a process of re-subdivision that is bounded by roads within Perth, Western Australia. For the same area we propose an alternative design with an urban infill model based on a medium density housing guidelines with an improved green space allocation. While the current model shows significant effects of UHIs we could mitigate those effects in the alternative proposed model. In our simulation the hottest surfaces are roads with a temperature of approximately 45 °C at 2PM in the afternoon. In the current model close to 100% of the road surfaces reach this temperature. In contrast, in the alternative model only 45% of all road surfaces reach this temperature, significantly reducing the impact of UHI for pedestrian walking close by to those roads. At 2PM, the most frequent temperature of all surfaces for the current model is around 44 °C while the alternative’s model the most frequent temperature is approximately 28 °C – a difference of 16 °C.

A 560 GHz Sub-Harmonic Mixer Using Half-Global Design Method

In this paper, a 560 GHz terahertz sub-harmonic mixer using a new half-global design method is reported. This method combines the advantages of the subdivision design method and the global design method, and greatly enhances the abilities of the optimization of matching variables while retaining the portability of the unit circuit. When the local oscillator (LO) frequency was fixed with 3 mW power at 280 GHz, average up-conversion double sideband (DSB) conversion loss of 8 dB with intermediate frequency (IF) power of −5 dBm was achieved.

A 200–240 GHz Sub-Harmonic Mixer Based on Half-Subdivision and Half-Global Design Method

For the terahertz harmonic mixer, a design model based on Half-Subdivision and Half-Global Design Method (HS-HGDM) with a single functional unit is proposed. The single functional unit circuit of the mixer, such as LO or IF Low Pass Filter (LPF), is designed by Subdivision Design Method (SDM), and the rest circuits of the mixer are designed by Global Design Method (GDM). The harmonic mixer based on this model is characterized by simple circuit structure, low conversion loss, small circuit size and high stability. In this paper, an improved Compact Suspended Micro-strip Resonators (CSMRs) filter is developed for the IF part of sub-harmonic mixer. The remaining circuits consist of some basic transmission units, such as the High-Z Low-Z impedance Transmission Lines (H-Z L-Z TLs) applied for main circuit, and full/reduced height WR4.3/WR8 applied for providing RF/LO signal. In RF frequency range 200–240 GHz, a Single Sideband (SSB) conversion loss of 7.36±0.76 dB operating at IF frequency 1.8 GHz, and a Double Sideband (DSB) noise temperature below 1034 K with the LO power of 2–5 mW and the LO frequency of 107 GHz were achieved. This broadband sub-harmonic mixer operates at room temperature, which makes it applicable to sub-millimeter wave or terahertz wireless communication systems and imaging inspection systems.

Design of 199 to 238 GHz broadband subharmonic mixer combining two‐stage reduced matching technology with Global Design Method

AbstractTerahertz technology is widely used in communications, radar, electronic countermeasures, precision guidance, and biomedical applications. In this paper, a 199 to 238 GHz broadband subharmonic mixer combining two‐stage reduced matching technology with Global Design Method is designed, fabricated, measured, and analysed successfully. Compared with traditional single‐stage reduced matching technology and Subdivision Design Method, the two‐stage reduced matching technology is applied for terahertz mixer's Radio Frequency (RF) waveguide and Local Frequency (LO) waveguide, while the LO/Intermediate Frequency (IF) Low‐Pass Filter of terahertz mixers is not necessary to design separately. The core of Global Design Method is that the whole mixer circuit, including LO/RF waveguide, is divided into basic transmission units, which match and filter circuit simultaneously with more optimization variables. When LO driven power is 3.1 mW, LO frequency is 108, 112 GHz. The measured single‐sideband (SSB) conversion loss ranges from 7.84 to 12.4 dB with RF frequency 199 to 238 GHz. The measured double‐sideband (DSB) noise temperature varies between 580 and 1059 K with LO driven power 2 to 5 mW. The multi‐stage reduced matching technology and Global Design Method is general, effective, accurate, can reduce circuit size, simplify circuit structure, broaden frequency band, and can be applied for terahertz harmonically mixers.

Communicating Biophilic Design: Start With the Grasslands

To protect remnant ecosystems within urban areas, guidelines are needed for the biophilic design, construction and ongoing occupation of the suburban subdivisions, industrial land or business parks surrounding them. Planners, urban designers, architects, landscape architects, road engineers and the community need tools to help design and manage urban landscapes in a way that puts the ecosystem’s requirements on par with urban development. The Victorian National Parks Association recognised this need and developed Start with the grasslands (SWTG) as a set of biophilic urban design guidelines to protect remnant grasslands within urban areas. South-eastern Australia’s grasslands are Australia’s most endangered ecosystem, with less than 2% remaining. Many are within or at the fringes of urban areas and are in continuing decline in extent and quality. Because of considerable challenges to acceptance, the development of these biophilic design guidelines was as important as the guidelines themselves. The process was structured to maximise inclusivity and stakeholder buy-in, educate, shift debate from traditional lines of argument, and to communicate the complex relationships to be negotiated for a successful outcome. The guidelines needed to be evidence-based, trans-disciplinary, and refer directly to on-the-ground case studies. Organisational partnerships further built legitimacy. Recommendations span spatial scales from the highly local to the regional and consider the full timescale of urban development. SWTG communicates through non-confrontational language and visual techniques.

Subdivision design and landscape structure: Case study of The Woodlands, Texas, US

The aim of this study was to investigate the relationship between subdivision design and landscape structure. The study outcome reveals how street-related design elements influence landscape structure, especially patch size, which represents species diversity and species distribution. Comparison analysis was conducted between two areas that had similar pre-development ecological conditions but were developed with different design approaches: ecological design approach and conventional development approach. Aerial photos of each area were classified as forested or non-forested, and landscape structure was quantified with six landscape metrics related to fragmentation. The ecologically planned community, which is designed with lower lot perimeter, narrower street width, and fewer number of intersections showed a less fragmented forest pattern and resulted in more ecologically structured environments. This study also revealed street-related design metrics were more significantly related to habitat fragmentation than parcel-related metrics. This study provides quantified landscape configuration and composition, showing the influence of design metrics on landscape structure. Understanding how elements of design metrics affect ecological landscape patterning is important for landscape architects and planners for planning and designing ecologically healthy environments.

A 220 GHz Broadband Sub-Harmonic Mixer Based on Global Design Method

A terahertz mixer is one of terahertz key components and widely used on terahertz wireless communication, remote sensing, aerospace exploration, and biomedical system. The performance of the terahertz mixer has a great effect on the entire terahertz transceiver system performance. This paper proposes a 220 GHz broadband sub-harmonic mixer based on global design method (GDM), which is different from the traditional subdivision design method of which the mixer circuit is composed of functional unit circuits. Instead, the GDM adopts the overall performance of the mixer (conversion loss) as an optimization goal. The continuous structures of the circuit are described by ideal transmission line models and waveguide models, meanwhile, the S-parameters of the de-embedded model are used to describe the discontinuous structures. The measured single-sideband (SSB) conversion loss is basically consistent with the simulation results, which verifies the accuracy and reliability of the GDM. When local oscillator (LO) frequency is fixed at 110 GHz, the measured SSB conversion loss is less than 10 dB with the average value of 8.1 dB from 198 to 238 GHz. The minimum conversion loss of the mixer is 6.35 dB at 207 GHz. The measured double-sideband noise temperature of the mixer is less than 924 K at an intermediate frequency of 1.6 GHz. The GDM has the characteristics with a wide frequency band, small circuit size, simple structure, low LO power, and stable performance, and can also be applied to other terahertz components.

Development of information technologies and algorithms for generation of block-structured adaptive grids in complex domains

The paper covers the area of block-structured adaptive grid generation for finite-difference, finite-element and finite-volume methods. It deals with a problem of development of information technologies and algorithms for generating of such grids in complex geometries. Its key idea is to bring together the different existing techniques for computer-aided geometric design of domains, grid generation, and subdivision. The methods used for a construction of domain geometries and working with block-structured quasi-continuous grids are discussed. The results in the generation of three-dimensional adaptive grids for the domain of external flow near a hemisphere, flow around a surface of the high-speed aircraft of the Falcon HTV-2 type and for the domain of the gap between a wheel and a body of an aircraft are analyzed. The presented methods and algorithms for grid generation have the following advantages: 1. The grids are structured and mesh cells are hexahedra in the entire domain. 2. The grids can be applied for finite-difference methods. 3. The grid lines are adjusting with the flow in the whole domain.

Subdivision design and stewardship affect bird and mammal use of conservation developments.

Developing effective tools for conservation on private lands is increasingly important for global biodiversity conservation; private lands are located in more productive and biologically diverse areas, and they face accelerated rates of land conversion. One strategy is conservation development (CD) subdivisions, which cluster houses in a small portion of a property and preserve the remaining land as protected open space. Despite widespread use, the characteristics that make CD more or less effective at achieving biodiversity conservation are not well understood. We investigated CD's ability to successfully protect animal populations by examining bird and mammal occurrences in 14 CD subdivisions and four undeveloped areas (range: 14-432ha) in northern Colorado, USA. Using point count and camera trap data in an occupancy modeling framework, we evaluated the relative importance of nine subdivision design factors (e.g., housing density, proportion of CD protected) and 14 stewardship factors (e.g., presence of livestock, percent native vegetation cover) in influencing the overall community composition and the probability of use by 16 birds and six mammals. We found that habitat use by 75% of birds and 83% of mammals was associated with design characteristics that maximized the natural or undisturbed land area both within and near the development (e.g., proportion of CD protected, total area of protected open space, proportion of natural land cover in the surrounding landscape). These factors were also associated with an increasing dominance of human-sensitive bird species, larger-bodied mammals, and mammals with larger home ranges. Habitat use by birds was also influenced by local land use composition and quality, and use by several bird and mammal species decreased with increased localized disturbances. We found few differences in habitat use between sampling sites in undeveloped areas and in CD subdivisions. These similarities indicate that, if CDs are large enough or located within a matrix of undeveloped land, they can provide habitat that supports similar use patterns as protected areas without housing development. By incorporating characteristics that promote the persistence of sensitive birds and mammals on private lands, CDs have potential to preserve native biodiversity in areas threatened by expanding residential development.

Pathways for optimal provision of thermal comfort and sustainability of residential housing in hot and humid tropics of Australia – A critical review

The optimal provision of thermal comfort and energy efficiency for residential housing in the hot and humid tropics presents challenges and opportunities for housing and subdivision designs. Climatic challenges come in the form of high ambient temperature and humidity, especially during the wet season and transition periods. On the other hand, climatic advantages come in the form of breezes coupled with relatively dry air during the dry season, enabling thermal comfort attainment through natural ventilation that employs prevailing breezes. This paper discusses existing design practices for housing and subdivisions in the hot and humid tropics with particular reference to the city of Darwin in Australia’s Northern Territory. This includes several research issues and gaps that have been identified and need to be addressed. The paper also critically assesses how air speed, air temperature and humidity – three of the thermal comfort parameters – play a key role in housing and subdivision design consideration in the hot and humid tropics. In doing so, the paper sheds light on the inadequacy of the current residential energy rating methodology as a tool for assessing tropical housing performance and proposes a new direction for future research to ameliorate these issues for the tropics.

Subdivision Design of Grating Moire Fringes and Simulation by Simulink

Subdivision Design of Grating Moire Fringes and Simulation by Simulink

Urban flooding and ground‐related homes in Canada: an overview

AbstractUrban flooding associated with extreme precipitation is a significant cause of disaster damages for municipalities, homeowners and insurers in Canada. Several approaches have been applied to reduce urban flood risk at the municipal and homeowner scales, including addressing inflow/infiltration in wastewater systems, accommodating extreme stormwater flows in subdivision design and protecting individual homes from flooding. Insurers have also engaged in managing urban flood risk through interactions with individual policyholders and initiatives aimed at better understanding urban flood risk and risk mitigation options. Requiring mitigation measures at the time of the construction of homes, improving insurance data, application of incentives for appropriate private side retrofits, and improved collaboration between insurers and municipalities for identification of urban flood risk areas provide additional opportunities for urban flood risk reduction. Further, senior levels of governments should support inflow/infiltration reduction and application of climate change information to improve the planning and design of municipal infrastructure.

Effects of Alternative Developer Decision-Making Models on the Production of Ecological Subdivision Designs: Experimental Results from an Agent-Based Model

Approaches to residential development have clear effects on the surrounding environments, including those on habitat protection, water quality, transportation and congestion costs, and loss of public open space. Ecological subdivision designs (ESDs) are a means to mitigate some of the most negative effects of low-density dispersed land-use patterns, yet there is not widespread adoption of these alternative approaches to subdivision development. In this paper we attempt to improve understanding of how developers make decisions over development designs and what influences those decisions. Using an agent-based model of residential-housing and land markets, the effects of different developer-decision frameworks on development designs and land use are assessed. The importance of uncertainty in the outcome of new designs, such as ESDs, and the effect of that uncertainty on the cost of credit are possible explanations for the prevalence of conventional, low-density development types, and may be impeding adoption of ESDs.