Practical Design Issues Research Articles

Aspects for systematization of scenario methods for architectural objects design

Concepts of creating a sustainable architectural environment require finding performance-based design methods, including scripting. Scenario design methods are based on the evaluation of possible variants of transformation of the object in time, and on the possibilities of dynamic use (and the perception of the object is use in real time), that is, its interactive vision. The purpose of this article is a general systematization of various scripting methods for designing architectural objects. The object of the study is an object of architecture as a whole ensemble, consisting of architecturally designed space and buildings that form this space and have certain features that combine them. The functions under the influence of which an architectural object is forming may change over time and in real time, and the aesthetic evaluation of its imaginative potential may be contribute to certain dynamic scenarios. The scenarios are classified according to the aspects of the requirements for architectures that were first identified Vitruvium: 1- utility or long-term functionality;2- durability, or in modern terminology, stability, reliability and durability; 3-beauty, or aesthetic appeal, expressiveness. Given the updated regulatory requirements for architectural objects and the typology of their perceptions, an extended list of aspects of scenario modeling are provide. The following classification features are use as approaches to the general systematization of scenario methods for forming architectural objects, which is a two-dimensional matrix in which horizontal bands (time axis) indicate the ranges in time of evaluating changes that may occur in an object. Functional binding of scenario methods to time ranges allows to solve a number of theoretical and practical issues of parametric design and to prevent conflicting interpretation of the field of use of scripting methods in the design of architectural objects.

Critical-Angle Differential Refractometry of Lossy Media: A Theoretical Study and Practical Design Issues

At a critical angle of incidence, Fresnel reflectance at an interface between a front transparent and a rear lossy medium exhibits sensitive dependencies on the complex refractive index of the latter. This effect facilitates the design of optical sensors exploiting single (or multiple) reflections inside a prism (or a parallel plate). We determine an empirical framework that captures performance specifications of this sensing scheme, including sensitivity, detection limit, range of linearity and—what we define here as—angular acceptance bandwidth. Subsequently, we develop an optimization protocol that accounts for all relevant optical or geometrical variables and that can be utilized in any application.

Practical issues in design and construction of dam earthworks

The paper describes examples of common pitfalls in design and construction of earthworks to construct dam embankments retaining large raised reservoirs, focusing mainly on new flood storage reservoirs. It concludes with key considerations for clients, engineers and contractors. It is intended as a briefing to less-experienced colleagues, rather than repeating information in standard textbooks. It is structured to follow the process from initial planning of the source(s) of earthworks through design and construction to operation and maintenance issues.

Synthesis of flexible heat exchanger networks: A review

Abstract Dealing with uncertainty is one of practical issues in design and operation of heat exchanger networks (HENs), arising the problem of flexible HEN synthesis. This paper addresses the state-of-the-art methods for flexible HEN synthesis based on sensitivity analysis, resilience analysis, flexibility analysis and multiperiod synthesis techniques as well. Each of these methods is summarized by presenting their general procedures and recent developments on modeling, solving strategies and applications. Some current topics related to flexible process synthesis have been briefly presented to provide several future research possibilities.

Optimization of height-wise damper distributions considering practical design issues

This paper discusses the optimal height-wise distribution of supplemental viscous dampers in multistorey building structures. Seismic excitation is modeled as stochastic stationary process and response statistics for linear structural systems are obtained through state-space analysis. For nonlinear damper applications statistical linearization is employed to accommodate a similar, state-space formulation. Emphasis is placed on three practical design issues: (i) realistic quantification of damper upfront cost based on damper force capacity rather than on the damping coefficient; (ii) investigation of bracing configuration schemes anchored at non-consecutive floor levels; and (iii) consideration of the cost of column strengthening required to accommodate the additional axial loads due to the supplemental damping system. Five different cost-based objective functions are defined to address these issues and the impact of each of them on the optimal damper distribution is examined in detail. Adjustments for estimation of peak responses when statistical linearization is used are also discussed. The optimal design problem considers the structural performance as a constraint, requiring that a target vibration suppression be achieved through the damper addition. An extension to a multi-objective design optimization is also discussed, incorporating the vibration suppression level as additional objective. The proposed approach is illustrated considering an actual Chilean 26-storey building subjected to an excitation compatible with the Chilean seismic hazard. Results show that damper distributions optimized considering realistic cost assessments are more efficient (with respect to cost-based design objectives) than distributions optimized considering simplified criteria. It is also demonstrated that consideration of practical issues such as column strengthening and feasible damper force capacity have a considerable influence on the optimal distribution. Finally, results also show that further cost reductions can be achieved with braces anchored at non-consecutive floor levels, and that such reductions are consistent with predictions given by approximate analytical expressions.

Allocating Students to Multidisciplinary Capstone Projects Using Discrete Optimization

We discuss an allocation mechanism of capstone projects to senior-year undergraduate students, which the recently established Singapore University of Technology and Design (SUTD) has implemented. A distinguishing feature of these projects is that they are multidisciplinary ; each project must involve students from at least two disciplines. This is an instance of a bipartite many-to-one matching problem with one-sided preferences and with additional lower and upper bounds on the number of students from the disciplines that must be matched to projects. This leads to challenges in applying many existing algorithms. We propose the use of discrete optimization to find an allocation that considers both efficiency and fairness. This provides flexibility in incorporating side constraints, which are often introduced in the final project allocation using inputs from the various stakeholders. Over a three-year period from 2015 to 2017, the average rank of the project allocated to the student is roughly halfway between their top two choices, with around 78 percent of the students assigned to projects in their top-three choices. We discuss practical design and optimization issues that arise in developing such an allocation.

Resolving Practical Design Issues in a Single-Phase Grid-Connected GaN-FET-Based Differential-Mode Inverter

Microinverters for grid-connected photovoltaic (PV) power conversion systems often require voltage boost due to the low dc voltage of the PV panels. A high-frequency (HF) transformer-isolated differential-mode Cuk inverter (DMCI) is an attractive topology due to its inherent voltage boost capability and high power density. One of the significant operational issue of the DMCI addressed in this paper is the presence of lower order harmonic distortion in the injected grid current. It is shown that lower order odd and even harmonic voltages are generated with this topology. This problem is accentuated due to the low damping offered by the grid to harmonic voltages. A systematic low-complexity control design is proposed to address this issue. It is shown experimentally that the DMCI operates stably with effective attenuation of the lower order harmonics using the proposed design. Practical operational issues of the DMCI with fast switching GaN field-effect transistor (FET) devices are analyzed and solutions are proposed. It is shown that there can be significant HF noise generation in the DMCI with a frequency range higher than the switching frequency. Practical solutions for resolving HF issues using a combination of circuit layout design and additional passive components are proposed and validated. All of the experimental results are demonstrated on a 500-W GaN-FET-based microinverter prototype.

Functional-power-aware Partial Gating Method for Low Power Scan-shift

This paper presents a new scheme to minimize scan-shift power for test reliability with minimized functional power overhead, which is achieved by selective insertion of signal gating-logic considering the loading condition and switching activity of scan shift signals. The proposed methodology also considers practical design issues such as logic-timing overhead and cell-congestion impact associated with scan-shift power reduction. In experimental results with industrial system-on-chip (SoC) designs, the proposed power-aware gatinglogic- insertion methodology not only achieved reduction of scan-shift power but also improved functional power up to 10% compared with the conventional full-scan gating scheme.

Carbon Taxation for International Maritime Fuels: Assessing the Options

The International Maritime Organization (IMO) announced in April 2018 a target of cutting greenhouse gas (GHG) emissions from the sector by 50 percent below 2008 levels by 2050 and subsequent meetings of the IMO will develop a strategy for making headway on this commitment. This paper seeks to inform dialogue about the possibility of a carbon tax as a key element of GHG mitigation policy for international maritime transport. The paper discusses the case for the tax over alternative mitigation instruments, options for the practical design issues, and then presents estimates of the impacts of carbon taxation and other instruments from an analytical model of the maritime sector.

Carbon Taxation for International Maritime Fuels: Assessing the Options

The International Maritime Organization (IMO) announced in April 2018 a target of cutting greenhouse gas (GHG) emissions from the sector by 50 percent below 2008 levels by 2050 and subsequent meetings of the IMO will develop a strategy for making headway on this commitment. This paper seeks to inform dialogue about the possibility of a carbon tax as a key element of GHG mitigation policy for international maritime transport. The paper discusses the case for the tax over alternative mitigation instruments, options for the practical design issues, and then presents estimates of the impacts of carbon taxation and other instruments from an analytical model of the maritime sector.

Pressure-Aware Control Layer Optimization for Flow-Based Microfluidic Biochips.

Flow-based microfluidic biochips are attracting increasing attention with successful biomedical applications. One critical issue with flow-based microfluidic biochips is the large number of microvalves that require peripheral control pins. Even using the broadcasting addressing scheme, i.e., one control pin controls multiple microvalves simultaneously, thousands of microvalves would still require hundreds of control prins, which is unrealistic. To address this critical challenge in control scalability, the control-layer multiplexer is introduced to effectively reduce the number of control pins into log scale of the number of microvalves. There are two practical design issues with the control-layer multiplexer: (1) the reliability issue caused by the frequent control-valve switching, and (2) the pressure degradation problem caused by the control-valve switching without pressure refreshing from the pressure source. This paper addresses these two design issues by the proposed Hamming-distance-based switching sequence optimization method and the XOR-based pressure refreshing method. Simulation results demonstrate the effectiveness and efficiency of the proposed methods with an average 77.2% (maximum 89.6%) improvement in total pressure refreshing cost, and an average 88.5% (maximum 90.0%) improvement in pressure deviation.

Toward Position-Only Time-Delayed Control for Uncertain Euler–Lagrange Systems: Experiments on Wheeled Mobile Robots

This letter addresses the various practical design issues of a continuous-time time-delayed control (TDC) and proposes a new controller to make the TDC more suitable and applicable for real-life systems. While TDC has been renowned for its robust performance and simplicity in form, it requires state-derivatives feedback which may not be available explicitly in practice; and multiple numerical differentiations of the noisy state data deteriorate performance by invoking measurement error. In this letter, position-only time-delayed control (POTDC) has been proposed for a class of Euler–Lagrange systems which encompasses a large class of practical systems such as robotic manipulators and unmanned mobile robots. Contrary to the conventional TDC, the proposed POTDC eliminates explicit requirement of velocity and acceleration feedbacks and uses only position information of present and past instances to estimate the velocity and acceleration terms. It thus alleviates the measurement error arising from a numerical computation of state-derivatives. Moreover, based on the Razumikhin theorem, continuous-time stability is rigorously analyzed with consideration of the time-delay element in POTDC, which indeed establishes a selection criterion for the sampling interval and provides the designer a range of sampling intervals for same choice of controller gains. This allows POTDC to be suitable for systems which specifically operate with high sampling intervals due to application requirement. Accordingly, experimental validations of POTDC are provided in comparison with TDC under various sampling intervals, using a wheeled mobile robot.

The Strengthening of Reinforced Concrete Structures

The contribution deals with a method of strengthening reinforced concrete structures. It focuses on the use of non-bonded steel tendons for beams and plates. The strengthening of columns with the help of steel bandages is discussed too. The behaviour of the strengthened items is described, as well as the practical design issues involved. The article also provides information on practical experience gained during the application of the strengthening method.Other possible applications for the strengthening method are discussed, such as the use of materials based on FRP (fibre reinforced polymer), and especially those based on glass.

Developing and Understanding Design Interventions in Relation to Industrial Symbiosis Dynamics

Symbiotic Urban Agriculture Networks (SUANs) are a specific class of symbiotic networks that intend to close material and energy loops from cities and urban agriculture. Private and public stakeholders in SUANs face difficulties in the implementation of technological and organisational design interventions due to the complex nature of the agricultural and urban environment. Current research on the dynamics of symbiotic networks, especially Industrial Symbiosis (IS), is based on historical data from practice, and provides only partly for an understanding of symbiotic networks as a sociotechnical complex adaptive system. By adding theory and methodology from Design Science, participatory methods, and by using agent-based modelling as a tool, prescriptive knowledge is developed in the form of grounded and tested design rules for SUANs. In this paper, we propose a conceptual Design Science method with the aim to develop an empirically validated participatory agent-based modelling strategy that guides sociotechnical design interventions in SUANs. In addition, we present a research agenda for further strategy, design intervention, and model development through case studies regarding SUANs. The research agenda complements the existing analytical work by adding a necessary Design Science approach, which contributes to bridging the gap between IS dynamics theory and practical complex design issues.

Programs of the preventive interventions against sexually transmitted infections in the high-risk subpopulations

A review article highlights the practical issues of design, implementation and effectiveness estimation of STI prevention programs aimed to correct the behavior leading to infection. the importance of epidemiological modeling method for the organization of preventive interventions is discussed. the prospects of the multidisciplinary behavioral approach to STI prevention are demonstrated.

Environmental monitoring network along a mountain valley using embedded controllers

This paper presents the design and implementation of an atmospheric observing system to study downslope winds in the Laja River Valley, southern-central Chile. Practical design issues are discussed based on the first two years of operation, as well as scientific results that demonstrate the potential of the measurement system. The system consists of a network of eight meteorological stations that characterize the winds along the Laja River Valley, Chile. The meteorological network extends over 90km, beginning with the station at the Antuco Ski Center at 1395m.a.s.l. and ending at the Charrua Electric Plant at 153m.a.s.l. The meteorological stations were designed to employ an embedded controller and high-performance instruments with low power consumption. In order to transmit data to the base station, a communication protocol was developed using SMS messages. Graphic tools are also available in the project webpage to visualize received data. Data reported in this work show that the meteorological network is able to identify and characterize downslope winds.

Control Circuits in Power Electronics: Practical Issues in Design and Implementation [Book News

This book discloses discloses some engineering solutions that usually have no place to be published in papers about control of power electronics converters. Although it is assumed that a skilled engineer can figure out how to implement a published modulator and nonlinear controller, often, the obtained solution is not optimal and takes valuable time. This book presents state-of-the-art techniques to implement modulation schemes, control algorithms, and gate drivers using analog circuits, digital microprocessors, or field-programmable gate arrays (FPGA). The book’s first part covers analog control circuits and converters where analog control circuitry presents higher performance. The second part, “Digital Control Circuits,” includes quantization effects and limit cycles, controller implementation, digital PWM, microcontrollerbased electronic ballasts, and FPGAs with sliding-mode direct control applied to unity power factor boost rectifiers (UPFRs). The third part, “New Trends in Control Circuits for Power Electronics,” starts with intelligent gate drivers, design and control of switched capacitor (charge pumps), and DSP natural frame and sliding-mode control of UPFRs at fixed switching frequency. The last chapters are dedicated to the application of dual-core DSPs in the control of grid-forming converters to microgrids and the usage of computational intelligence (fitness functions, genetic algorithms, and ant colony optimization) to optimize power converters.

Cognitive Capacity Harvesting Networks: Architectural Evolution Toward Future Cognitive Radio Networks

Cognitive radio technologies enable users to opportunistically access unused licensed spectrum and are viewed as a promising way to deal with the current spectrum crisis. Over the last 15 years, cognitive radio technologies have been extensively studied from algorithmic design to practical implementation. One pressing and fundamental problem is how to integrate cognitive radios into current wireless networks to enhance network capacity and improve users’ experience. Unfortunately, existing solutions to cognitive radio networks (CRNs) suffer from many practical design issues. To foster further research activities in this direction, we attempt to provide a tutorial for CRN architecture design. Noticing that an effective architecture for CRNs is still lacking, in this tutorial, we systematically summarize the principles for CRN architecture design and present a novel flexible network architecture, termed cognitive capacity harvesting network (CCHN), to elaborate on how a CRN architecture can be designed. Unlike existing architectures, we introduce a new network entity, called secondary service provider, and deploy cognitive radio capability enabled routers, called cognitive radio routers, in order to effectively and efficiently manage resource harvesting and mobile traffic while enabling users without cognitive radios to access and enjoy CCHN services. Our analysis shows that our CCHN aligns well to industrial standardization activities and hence provides a viable approach to implementing future CRNs. We hope that our proposed design approach opens a new venue to future CRN research.

Perforated tunnel exit regions and micro-pressure waves: geometrical influence

The effectiveness of long, perforated exit regions in reducing the radiation of micro-pressure waves (MPWs) from railway tunnels is assessed. Such disturbances always occur, but their amplitudes are usually small. For the particular case of high-speed trains, they can reach levels that would cause annoyance in the absence of suitable countermeasures. This risk is especially large in the case of long tunnels. The general behaviour of wave reflection/transmission/radiation at a perforated exit region has been explored in previous papers that have (a) quantified the dependence on the characteristics of the incident wavefront reaching the exit region from further upstream in the tunnel and (b) validated the numerical methodology in a searching manner. Some notable differences have been found in comparison with the criteria that have long been known for unperforated exit regions. In particular, the resulting MPW amplitudes depend on the amplitudes of incident wavefronts as well as on their steepnesses. This paper summarises these outcomes and uses the methodology to explore important practical design issues, namely the dependence of the effectiveness of perforated exit regions on their length and cross-sectional area. Once again, differences are found from the behaviour of unperforated regions.

姿勢安定走行を可能とする形状可変クローラ機構

This paper presents practical design and hardware implementation issues of an adaptable crawler mechanism for a mobile robot, enabling the robot to maintaining its constant posture when roving. For the purpose, we propose a novel multi-legged adaptable crawler (MLAC) device based on a spring and a rack-and-pinion unit. Specially, the MLAC device allows to change the crawler configuration in order to adapt to a local surface geometry. When the MLAC device is mounted under the robot body, even though the robot encounters ascending/descending slopes and thresholds, the mechanism allows it to preserve its locomotive posture constantly. The design and features of the MLAC device are explained in detail, and its effectiveness is verified through extensive experiments in everyday environments.