Architectural Alternatives Research Articles

Framework for Engineering Design Systems Architectures Evaluation and Selection: Case Study

Engineering companies face the challenge of developing complex Engineering Design Systems. These systems involve huge financial, people, and time investments within an environment that is characterised by continuously changing technologies and processes. Systems architecture provides the strategies and modelling approaches to ensure that adequate resources are spent in developing the possible To Be states for a target system. Architecture selection and evaluation involves evaluating different architectural alternatives with respect to multiple criteria, hence an Architecture Evaluation Framework which evaluates and down selects the appropriate architectures solutions is crucial to assess how these systems will deliver value over their lifetime, and where to channel the financial and human investments to maximize benefit delivered to the business’ bottom line.In this paper, an evaluation and selection architecture framework is proposed, which targets to maximise the alignment of Engineering Design Systems with business goals based on a quality centric architecture evaluation approach. The framework utilised software Quality Attributes as well as SWOT (Strength, Weakness, Opportunity, Threat) and PEST (Political, Economic, Social, Technological) analyses to capture different viewpoints related to technical, political and business context. The framework proposed employing AHP (Analytical Hierarchy Process) to quantitatively elicit relationships between Quality Attributes trade-offs and architectural characteristics. The framework was applied to a real case study considering five Engineering Design Systems alternative architectures, where workshops with subject matter experts and stakeholders were held to reach an informative decision, that maximise architectural quality, whilst maintaining business alignment.

Architecture optimization: speed or accuracy? both!

Embedded systems are becoming more and more complex, thus demanding innovative means to tame their challenging development. Among others, early architecture optimization represents a crucial activity in the development of embedded systems to maximise the usage of their limited resources and to respect their real-time requirements. Typically, architecture optimization seeks good architecture candidates based on model-based analysis. Leveraging abstractions and estimates, this analysis usually produces approximations useful for comparing architecture candidates. Nonetheless, approximations do not provide enough accuracy in estimating crucial extra-functional properties. In this article, we provide an architecture optimization framework that profits from both the speed of model-based predictions and the accuracy of execution-based measurements. Model-based optimization rapidly finds a good architecture candidate, which is refined through optimization based on monitored executions of automatically generated code. Moreover, the framework enables the developer to leverage her optimization experience. More specifically, the developer can use runtime monitoring of generated code execution to manually adjust task allocation at modeling level, and commit the changes without halting execution. In the article, our architecture optimization mechanism is first described from a general point of view and then exploited for optimizing the allocation of software tasks to the processing cores of a multicore embedded system; we target extra-functional properties that can be concretely represented and automatically compared for different architectural alternatives (such as memory consumption, energy consumption, or response-time).

Architectural modifications for flexible supercapacitor performance optimization

We have developed material and architectural alternatives for flexible supercapacitors and investigated their effect on practical performance. The substrate alternatives include paperboard as well as various polyethylene terephthalate (PET) films and laminates, with aqueous NaCl electrolyte used in all devices. In all the supercapacitors, activated carbon is used as the active layer and graphite ink as the current collector, with various aluminium or copper structures applied to enhance the current collectors’ conductivity. The capacitance of the supercapacitors was between 0.05 F and 0.58 F and their equivalent series resistance (ESR) was from <1 Ω to 14 Ω, depending mainly on the current collector structure. Furthermore, leakage current and selfdischarge rates were defined and compared for the various architectures. The barrier properties of the supercapacitor encapsulation have a clear correlation with leakage current, as was clearly shown by the lower leakage in devices with an aluminium barrier layer. A cycle life test showed that after 40000 charge-discharge cycles the capacitance decreases by less than 10%.

End-to-End Delay Bound Analysis for Location-Based Routing in Hybrid Vehicular Networks

There is an ongoing debate in the research and industry communities as to whether IEEE 802.11p or Third-Generation Partnership Project (3GPP) Long-Term Evolution (LTE) should be used for vehicular communications. In this paper, we argue that a hybrid vehicular network combining both technologies can increase the performance of the system. We first propose a mechanism to improve location-based routing in a hybrid vehicular network architecture by data and signaling traffic separation on independent wireless networks. We then develop analytical models to calculate the stochastic upper bound of the end-to-end delay (E2ED) for location-based routing in three different networking architecture alternatives based on a) short-range ad hoc only, b) cellular only, and c) the proposed hybrid ad hoc/cellular network. The analytical approach in this paper is based on the stochastic network calculus (SNC) theory, which provides a solid and uniform framework for analysis of the upper bound of the E2ED in communication networks. It is demonstrated that the proposed hybrid network provides a lower E2ED compared with the other two alternatives. Comparisons of realistic simulation results, carried out in NS-3, and analytical results show that the proposed delay bounds provide relatively tight approximations for the E2ED in the three alternative architectures for vehicular networks investigated in this paper.

Improving software performance and reliability in a distributed and concurrent environment with an architecture-based self-adaptive framework

More and more, modern software systems in a distributed and parallel environment are becoming highly complex and difficult to manage. A self-adaptive approach that integrates monitoring, analyzing, and actuation functionalities has the potential to accommodate an ever dynamically changing environment. This paper proposes an architecture-level self-adaptive framework with the aim of improving performance and reliability. To meet such a goal, this paper presents a Self-Adaptive Framework for Concurrency Architectures (SAFCA) that consists of multiple well-documented architectural patterns in addition to monitoring and adaptive capabilities. With this framework, a system using an architectural alternative can activate another alternative at runtime to cope with increasing demands or to recover from failure. Five adaptation mechanisms have been developed for concept demonstration and evaluation; four focus on performance improvement and one deals with failover and reliability enhancement. We have performed a number of experiments with this framework. The experimental results demonstrate that the proposed adaptive framework can mitigate the over-provisioning method commonly used in practice. As a result, resource usage becomes more efficient for most normal conditions, while the system is still able to effectively handle bursty or growing demands using an adaptive mechanism. The performance of SAFCA is also better than systems using only standalone architectural alternatives without an adaptation scheme. Moreover, the experimental results show that a fast recovery can be realized in the case of failure by conducting an architecture switchover to maintain the desired service.

Automated Metabolic P System Placement in FPGA

Abstract An original Very High Speed Integrated Circuit Hardware Description Language (VHDL) code generation tool that can be used to automate Metabolic P (MP) system implementation in hardware such as Field Programmable Gate Arrays (FPGA) is described. Unlike P systems, MP systems use a single membrane in their computations. Nevertheless, there are many biological processes that have been successfully modeled by MP systems in software. This is the first attempt to analyze MP system hardware implementations. Two different MP systems are investigated with the purpose of verifying the developed software: the model of glucose–insulin interactions in the Intravenous Glucose Tolerance Test (IVGTT), and the Non-Photochemical Quenching process. The implemented systems’ calculation accuracy and hardware resource usage are examined. It is found that code generation tool works adequately; however, a final decision has to be done by the developer because sometimes several implementation architecture alternatives have to be considered. As an archetypical example serves the IVGTT MP systems’ 21–23 bits FPGA implementation manifesting this in the Digital Signal Processor (DSP), slice, and 4-input LUT usage.

Decomposition-Based Design Optimization of Hybrid Electric Powertrain Architectures: Simultaneous Configuration and Sizing Design

Effective electrification of automotive vehicles requires designing the powertrain's configuration along with sizing its components for a particular vehicle type. Employing planetary gear (PG) systems in hybrid electric vehicle (HEV) powertrain architectures allows various architecture alternatives to be explored, including single-mode architectures that are based on a fixed configuration and multimode architectures that allow switching power flow configuration during vehicle operation. Previous studies have addressed the configuration and sizing problems separately. However, the two problems are coupled and must be optimized together to achieve system optimality. An all-in-one (AIO) system solution approach to the combined problem is not viable due to the high complexity of the resulting optimization problem. This paper presents a partitioning and coordination strategy based on analytical target cascading (ATC) for simultaneous design of powertrain configuration and sizing for given vehicle applications. The capability of the proposed design framework is demonstrated by designing powertrains with one and two PGs for a midsize passenger vehicle.

Synthesis of Application-Specific Fault-Tolerant Digital Microfluidic Biochip Architectures

Digital microfluidic biochips (DMBs) are microfluidic devices that manipulate droplets on an array of electrodes. Microfluidic operations, such as transport, mixing, and split, are performed on the electrode array to perform a biochemical application. All previous work assumes that the DMB architecture is given and most approaches consider a rectangular shape for the electrode array. However, nonrectangular application-specific architectures are common in practice. Hence, in this paper, we propose an approach to the synthesis of application-specific architectures, such that the cost of the architecture is minimized and the timing constraints of the biochemical application are satisfied. DMBs can be affected by permanent faults, which may lead to the failure of the biochemical application. Our approach introduces redundant electrodes to synthesize fault-tolerant architectures aiming at increasing the yield of DMBs. We have used a tabu search metaheuristic for this architecture synthesis problem. We have proposed a technique to evaluate the architecture alternatives visited during the search, in terms of their impact on the timing constraints of the application. The proposed architecture synthesis approach has been evaluated using several benchmarks.

Using a mock simulation event and Monte Carlo simulation to compare alternative network architectures for distributed training simulation

A systems engineering effort produced three alternative network architectures for a system to support simulation-based training events. A mock simulation event was used to compare the effort required for each alternative to prepare for, conduct, and analyze an event. The mock event was a manual execution of a process for conducting simulation events consisting of a sequence of defined activities. As a mock event, no simulations were executed and the activities’ work was not performed. Instead, the labor required for each activity for each alternative was estimated by simulation subject matter experts using the Delphi method. The experts’ estimates drove a set of Monte Carlo trials. Probability distributions were parameterized with the estimates, from which values for the labor required for each activity for each alternative were stochastically generated. Those values were summed to estimate the mean total labor required for an event for each alternative. Confidence intervals for each alternative’s labor did not overlap, and hypothesis tests confirmed that the alternatives’ labor requirements were statistically different. The methodology, which combined a mock simulation event, Delphi estimation, Monte Carlo simulation, and statistical analysis, is likely to be useful in similar situations where simulation system architecture alternatives are compared before implementation.

America in Ruins: Cooper, Child, and the Problem of the National House

This essay examines the ways in which American authors writing what were some of the first “American” novels included images of buildings being razed, pulled down, and otherwise demolished. Specifically, I argue that the houses at the heart of two early revolutionary romances--James Fenimore Cooper’s wildly popular The Spy, a Tale of the Neutral Ground (1821) and Lydia Maria Child’s highly anticipated second novel, The Rebels; or, Boston before the Revolution (1825)--function as examples of European architecture and architectural-imaginary practices. These authors are responding to a desire for a unique American architectural archive that would, as Thomas Jefferson hoped, relfect the new nation’s history and identity. Yet, the design of these houses and their material afterlives frustrate a neat narrative of architectural-national progression. Though these houses closely resemble their European cousins (English country houses and Enlightenment temples) their destruction does not signal a hopeful moment of (re)constructing American national Identity. Rather, the destruction of these homes registers a moment of deep pathos and trauma in both novels and in the wake of their destruction, no architectural alternative appears to record the nation’s history.

Methodological evaluation of architectural alternatives for an aeronautical delay tolerant network

In this paper, we use graph analysis to evaluate the network architecture of a large scale delay tolerant network (DTN) of transoceanic aircraft. At LCN (Local Computer Networks) 2014 we analyzed information propagation inside a pure opportunistic version of this network, a scenario constructed from more than 2,500 traces of transatlantic flights in which communications relied only on the sporadic contacts between airplanes. As only a small percentage of the nodes were capable of performing efficient air-to-ground communications we concluded the need to devise a more suitable network architecture by combining opportunistic and satellite communication systems. We propose a generic methodology based on graph analysis (both static and dynamic temporal) to evaluate the different ways to create this new architecture. We show the architectural combination that most improves the network delivery performance while minimizing its deployment costs.

An Architecture-Based Multi-Objective Optimization Approach to Testing Resource Allocation

Software systems are widely employed in society. With a limited amount of testing resource available, testing resource allocation among components of a software system becomes an important issue. Most existing research on the testing resource allocation problem takes a single-objective optimization approach, which may not adequately address all the concerns in the decision-making process. In this paper, an architecture-based multi-objective optimization approach to testing resource allocation is proposed. An architecture-based model is used for system reliability assessment, which has the advantage of explicitly considering system architecture over the reliability block diagram (RBD)-based models, and has good flexibility to different architectural alternatives and component changes. A system cost modeling approach which is based on well-developed software cost models is proposed, which would be a more flexible, suitable approach to the cost modeling of software than the approach adopted by others which is based on an empirical cost model. A multi-objective optimization model is developed for the testing resource allocation problem, in which the three major concerns in the testing resource allocation problem, i.e., system reliability, system cost, and the total amount of testing resource consumed, are taken into consideration. A multi-objective evolutionary algorithm (MOEA), called multi-objective differential evolution based on weighted normalized sum (WNS-MODE), is developed. Experimental studies are presented, and the experiments show several results. 1) The proposed architecture-based multi-objective optimization approach can identify the testing resource allocation strategy which has a good trade-off among optimization objectives. 2) The developed WNS-MODE is better than the MOEA developed in recent research, called HaD-MOEA, in terms of both solution quality and computational efficiency. 3) The WNS-MODE seems quite robust from the sensitivity analysis results.

SPIRIT: Spectral-Aware Pareto Iterative Refinement Optimization for Supervised High-Level Synthesis

Supervised high-level synthesis (HLS) is a new class of design problems where exploration strategies play the role of supervisor for tuning an HLS engine. The complexity of the problem is increased due to the large set of tunable parameters exposed by the “new wave” of HLS tools that include not only architectural alternatives but also compiler transformations. In this paper, we developed a novel exploration approach, called spectral-aware Pareto iterative refinement, that exploits response surface models (RSMs) and spectral analysis for predicting the quality of the design points without resorting to costly architectural synthesis procedures. We show that the target solution space can be accurately modeled through RSMs, thus enabling a speedup of the overall exploration without compromising the quality of results. Furthermore, we introduce the usage of spectral techniques to find high variance regions of the design space that require analysis for improving the RSMs prediction accuracy.

A metric to assist the product families architecture definition

It is difficult to define products architecture for two main reasons: the high number of architecture alternatives and the lack of an evaluation criteria to these options. This article addresses the alternative architectures evaluation issue using a cost estimate approach. The purpose of this study is to describe a metric that assists the product architecture definition. The metric showed here is built over the relative estimates of the developing and assembly costs and was created as a tool to define a product family architecture; It uses the products cost estimates and functional descriptions. In addition to describing the metric that helps to define the product architecture, this article also illustrates its application to a family of four products sharing the same functional model. Finally, the metric presented is analyzed, as well as the potential to its use with computational algorithms to deal with complex problems.

A Holistic Approach for the Development and Implementation of Robust and Cost-Effective Enterprise WebGIS Business Solutions

Recent advancements in internet mapping technology, efficient geospatial data management systems, and availability of different GIS API’s have revolutionized the way in which the geospatial data is being used, shared and represented through distributed systems for business applications. However, development of powerful, highly functional, yet cost- and time-effective enterprise WebGIS business systems requires a very robust and highly scalable architecture. The architecture should have the inherent characteristics of rapid development, a well-defined object library and at the same time it should comply with the existing geospatial interoperability standards defined by Open Geospatial Consortium (OGC). On the other hand, development of extendible distributed business GIS systems requires the presence of tailor-made inbuilt models available as modules which can be extended further by readily implementable user-interface templates supported by object modeling environment which allows for custom design and delivery of the processes and map output. There are various commercial and open source web mapping solutions which offer a great deal of flexibility and functionality. Nevertheless, they restrict the user community with certain limitations, in terms of functionality, cost or complexity. This necessitates, defining a new approach which efficiently caters the user requirements and not limiting them with aforementioned shortcomings. This paper aims to evaluate various architectural alternatives for delivering robust distributed GIS business solutions and also attempts to give an account of an implementable instance of a WebGIS architecture which can cater the multi-user and multi-industry requirements.

Advances on Smart Object Management

The first part of this issue features four papers that discuss advanced management techniques for Smart Objects. The socalled Internet of Things (IoT) is one of the cornerstones of the Future Internet. One illustrative example of the relevance of IoT in future network development is its growing adoption within the smart city paradigm, as a means to provide enhanced citizen services. In this sense, basic IoT technology is no longer at the purely academic research level, but is starting to be integrated to the the fabric of our daily activities. One of the elements that are required to support the successful deployment of this type of architectures is having the appropriate management mechanisms in place. The call for papers for this special issue was a result of a dedicated workshop on the management of smart objects. The workshop was collocated with the 4th International Conference on Mobile Networks and Management (MONAMI 2012), which was organized in close collaboration with the Technical University of Hamburg in September 2012 (see www.mon-ami.org/2012). The four papers which were accepted for publication in this special issue deal with management architecture alternatives, service development frameworks, security challenges, and the role that contextual information has in the Internet of Things. All in all, they provide a comprehensive outlook on some of the problems that need to be addressed for this type of deployments. It is worth highlighting that three of the works do really exemplify the need of real deployments and employ implementation over existing technologies to assess the feasibility of their proposed architectures, frameworks and techniques. In the first paper, JaeSeung Song et al. review some of the architectural choices for M2M networks. They start from the challenges that need to be addressed and discuss how the various standardization bodies (for instance, ETSI and 3GPP) are tackling them. They then present their approach for some of the technical functionalities required to control and manage M2M networks. Finally the authors describe a realization of a subset of the aforementioned techniques over a real testbed, using the service model proposed by the SENSEI European project. The authors use three performance indicators to assess the goodness of the techniques, namely the stability, the scalability and the robustness. The results, that are as well included within the CAMPUS 21 project, show that the proposed scheme can run on relatively low-memory devices, making it very attractive for realworld IoT deployments. One key success factor for IoT is the possibility to enable fast service creation, which is open to the general public, so that a user does not need to be an expert to be able to create his/her own service. In order to address these challenges, Sylvain Cherrier et al. propose, in the second paper of this special issue, a framework to deploy services to be used over IoT based on the composition of behaviours. They go beyond their previous proposal, D-Lite, which was based on Finite State Transducers, and propose a simpler way of modeling the interactions between IoT components. The BeC3 architecture also allows the exploitation of available modules and K. Pentikousis (*) European Center for Information and Communication Technologies (EICT), EUREF Campus Haus 13, Torgauer Strase 12-15, 10829 Berlin, Germany e-mail: k.pentikousis@eict.de

On building architecture-centric product line architecture

Software architects typically spend a great deal of time and effort exploring uncertainties, evaluating alternatives, and balancing the concerns of stakeholders. Selecting the best architecture to meet both the functional and non-functional requirements is a critical but difficult task, especially at the early stage of software development when there may be many uncertainties. For example, how will a technology match the operational or performance expectations in reality? This paper presents an approach to building architecture-centric product line. The main objective of the proposed approach is to support effective requirements validation and architectural prototyping for the application-level software. Architectural prototyping is practically essential to architecture design and evaluation. However, architectural prototyping practiced in the field mostly is not used to explore alternatives. Effective construction and evaluation of multiple architecture alternatives is one of the critically challenging tasks. The product line architecture advocated in this paper consists of multiple software architecture alternatives, from which the architect can select and rapidly generate a working application prototype. The paper presents a case study of developing a framework that is primarily built with robust architecture patterns in distributed and concurrent computing and includes variation mechanisms to support various applications even in different domains. The development process of the framework is an application of software product line engineering with an aim to effectively facilitate upfront requirements analysis for an application and rapid architectural prototyping to explore and evaluate architecture alternatives.

서울시 단독주택지의 독립형 저층공동주택 제안에 관한 연구 - 답십리 재건주택지를 중심으로 -

As a measures for improving a housing environment, this study suggests a planning of detached low-rise multi-plex houses, which are applicable to part of the reconstruction housing site in Dapsipri, one of the detached public housing sites constructed in 1956. The purpose of this study is to suggest an architectural alternative, which can improve the quality of dwelling while maintaining the residential environment of the detached housing site. The planning of detached low-rise multi-plex houses for the reconstruction housing site in Dapsipri has the following features: 1)This planning ensures the equal quality of sunlight environment by considering the current physical housing density and by arranging four types of unit housing modules which consider the width and direction of streets. 2) This planning uses a rehabilitation redevelopment method for each lot, which has dilapidated buildings. This approach will be able to maintain previous housing lots and road systems where various housing groups have been formed over the years in the reconstruction housing site. 3)This planning provides an easy access to roads by increasing the width of inner streets within unit housing and by considering the geographical condition of each lot. 4)This planning provides community space to ensure connectivity among residents and to revitalize communications among residents. It designs public streets as a community space through an inward common space, which directs toward housing blocks, in addition to the outward common space, which directs toward the roads. This study discovered that the current residential environment of the Dapsipri reconstruction housing site is poor. To improve such a poor living environment, this study suggests a detached low-rise apartment planning, which still maintains the existing housing density and the existing geographical context, by taking a rehabilitation redevelopment approach. The planning suggested in this study will be able to restore physical rationality. However, it will face limitations in improving residents' awareness about redevelopment and in leading to a flexible interpretation of the related laws.

Modeling and optimization of multiple unmanned aerial vehicles system architecture alternatives.

Unmanned aerial vehicle (UAV) systems have already been used in civilian activities, although very limitedly. Confronted different types of tasks, multi UAVs usually need to be coordinated. This can be extracted as a multi UAVs system architecture problem. Based on the general system architecture problem, a specific description of the multi UAVs system architecture problem is presented. Then the corresponding optimization problem and an efficient genetic algorithm with a refined crossover operator (GA-RX) is proposed to accomplish the architecting process iteratively in the rest of this paper. The availability and effectiveness of overall method is validated using 2 simulations based on 2 different scenarios.

Performance evaluation of current and emerging authentication schemes for future 3GPP network architectures

One of the key issues in recent mobile telecommunication is to increase the scalability of current packet data networks. A challenging topic of scalability is the efficient handling of rapidly growing Machine-type communication, which comes along with the requirement of low-cost network attachment and re-attachment procedures.In this paper we present the results of a comprehensive testbed-based performance evaluation on a set of authentication schemes over “centralized”, “distributed” and “flat” mobile network architecture alternatives in terms of computational cost, memory utilization, authentication delay, and signalling overhead. The aim of our measurement and analysis is to facilitate decision making on authentication scheme selection in future mobile networks and in Wireless Personal Area Networks. We also show that the optimal distribution level of the network architecture is “distributed” with respect to the authentication delay. The studied authentication schemes seem to hinder seamless handover provision in case of frequent gateway changes, except the Host Identity Protocol-based Diet Exchange extended with 3GPP Authentication and Key Agreement authentication scheme over Wi-Fi access.