Architectural Alternatives Research Articles

Overview of Architectural Alternatives for the Integration of ETSI MEC Environments from Different Administrative Domains

Multi-access Edge Computing (MEC) is proposed as a standard framework for the provision and consumption of applications and services in proximity to the end-users of network operators. Proximity has been identified as one of the enablers of the forthcoming 5G, where extreme low latency and large bandwidth will be necessary for some services. However, the need of proximity imposes to network operators the necessity of huge investments in order to distribute computing capabilities towards the access. A less investment intensive approach would consist on sharing infrastructures by integrating MEC environments from different operators or providers. This could open the door to new business models on the one hand, as well as to avoid restrictions in terms of space, energy of regulation, on the other. This paper overviews different integration options by analyzing the MEC framework defined by the European Telecommunications Standards Institute (ETSI) and identifying different architectural alternatives as well as the business and technical aspects that need to be taken into consideration for realizing such integration.

Enabling Multicast and Broadcast in the 5G Core for Converged Fixed and Mobile Networks

The fifth generation of cellular technologies, 5G, promises to deliver a wide variety of services. However, the first release of 5G (3GPP Rel-15) did not consider multicast capabilities in the 5G system including both access and core networks. This article fills the gap by describing solutions for 5G mobile core network architecture incorporating multicast and broadcast capabilities. Two innovative solutions to provision multicast and broadcast, based on 3GPP Rel-15 arechitecture, have been proposed and analyzed. One is 5G architecture friendly with low imprint over Rel-15 while the other is based on the evolution of LTE Broadcast architecture. The architectural solutions feature two new main transmission modes: transparent multicast transport and point-to-multipoint services. The former enables the 5G network as a network pipe supporting multicast traffic providing a cost-effective delivery mode for multimedia while the latter enables multicast and broadcast as a service. The paper also presents a convergent fixed wireline and mobile network architecture based on the proposed mobile network architecture altenatives. The proposed architecture alternatives are suitable for different verticals and applications such as Digital Terrestrial Television, Public Warning, Internet of Things, V2X (vehicle to everything) and mission critical communications (MCC).

Architectural Design Alternatives Based on Cloud/Edge/Fog Computing for Connected Vehicles

As vehicles playing an increasingly important role in people's daily life, requirements on safer and more comfortable driving experience have arisen. Connected vehicles (CVs) can provide enabling technologies to realize these requirements and have attracted widespread attentions from both academia and industry. These requirements ask for a well-designed computing architecture to support the Quality-of-Service (QoS) of CV applications. Computation offloading techniques, such as cloud, edge, and fog computing, can help CVs process computation-intensive and large-scale computing tasks. Additionally, different cloud/edge/fog computing architectures are suitable for supporting different types of CV applications with highly different QoS requirements, which demonstrates the importance of the computing architecture design. However, most of the existing surveys on cloud/edge/fog computing for CVs overlook the computing architecture design, where they (i) only focus on one specific computing architecture and (ii) lack discussions on benefits, research challenges, and system requirements of different architectural alternatives. In this paper, we provide a comprehensive survey on different architectural design alternatives based on cloud/edge/fog computing for CVs. The contributions of this paper are: (i) providing a comprehensive literature survey on existing proposed architectural design alternatives based on cloud/edge/fog computing for CVs, (ii) proposing a new classification of computing architectures based on cloud/edge/fog computing for CVs: computation-aided and computation-enabled architectures, (iii) presenting a holistic comparison among different cloud/edge/fog computing architectures for CVs based on functional requirements of CV systems, including advantages, disadvantages, and research challenges.

Exploiting Queuing Networks to Model and Assess the Performance of Self-Adaptive Software Systems: A Survey

Abstract Self-adaptation has emerged as a primary concern in the context of modern software systems, due to the high dynamicity of the environments where they operate, which implies the need for such systems to properly face significant degrees of uncertainty. To this aim, much work has been done, mainly by coupling autonomic managers to the managed subsystem which perceives and affects the environment through its sensors and actuators, respectively. Such coupling often results into MAPE-K feedback loop(s), i.e. a Knowledge (K)-based architectural model that divides the adaptation process into four activities, namely Monitor (M), Analyze (A), Plan (P) and Execute (E). Performance modeling notations, analysis methods and tools, have been exploited and coupled to other kinds of techniques (e.g. control theory, machine learning) for modeling and assessing the performance of autonomic managers, possibly aimed at supporting the identification of more convenient architectural alternatives. Since moving in such a big arena is not trivial and it is easy to be overwhelmed, in this literature survey, we focus on a particular performance modeling paradigm, namely Queuing Networks, with the aim of clarifying the state-of-art in exploiting such a notation to model and assess performance of Self-Adaptive Software Systems. We conclude by bringing out some research opportunities that may be worth exploring in the near future.

A matching game for tasks offloading in integrated edge‐fog computing systems

AbstractEdge and fog computing paradigms have recently emerged as promising approaches to overcome latency and network congestion drawbacks of the cloud network architecture alternative. In this direction, the paper deals with an integrated edge‐fog computing system to provide computational offloading capabilities to end‐devices by assuming that each task can be alternatively run locally at the end‐device site, offloaded to a nearby device through a direct communication link (ie, device‐to‐device) or to a more far and computational powerful node, ie, a fog node. In particular, the goal of this paper is to identify a suitable tasks allocation strategy in order to minimize both the system energy consumption and the worst overall task completion time. The related optimization problem is formulated here as a matching game with externalities with incomplete preferences lists between tasks and computation sites due to the fact that each end‐device can reach only a subset of the fog nodes of the integrated computing system. Furthermore, this paper pursuits the stability analysis of the outcome matching, and provides a post matching procedure to reach a stable final matching configuration. Finally, the good behavior of the proposed approach is validated by providing performance comparisons with different alternatives, namely a typical cloud approach architecture, potential game and other matching theory based approaches recently proposed in literature.

Urban photovoltaic potential estimation based on architectural conditions, production-demand matching, storage and the incorporation of new eco-efficient loads

The photovoltaic solar potential in an urban sector and the effects produced by the electricity input into a low-voltage grid are determined, the analysis is performed for one year. First, the generation profiles are estimated, assuming the incorporation limits of typical silica panels and using photovoltaic (PV) tiles on roofs as an architectural alternative. Then, the consumer class demand is estimated. Production-demand matching is performed at the load point level to avoid impacts on the grid. A scenario incorporating a new load, induction heating cookers (IHCs) for all residential users, is posed, the use of which coincides with high-radiation hours. Finally, electrical storage is assumed to maximise the PV supply. A 16% coverage with silica PV panels, or 33% with PV tiles, would supply 46% or 39% of the consumption, respectively. With massive incorporation of IHCs and storage, the supply is increased to 73% and 59% of the consumption with silica panels and PV tiles, respectively. An annual consumption reduction of 16 Tn of liquefied petroleum gas is attained in the cases studied. Additionally, it is necessary to redirect the current subsidies for hydro dams and the overall energy sector towards promoting distributed microgeneration.

Evolution of Orchestration towards 5G

Service orchestration is an essential activity in 5G networks. It performs optimal resource allocation and provisions services in an effective sequence based on demands across a collection of physical or virtual network functions (P/VNF). This paper summarizes several orchestration environments and components along with their evolution towards 5G. A brief operational comparison of platforms such as Open Source Management and Orchestration (OSM MANO), Open Platform for NFV (OPNFV) and Open Network Automation Platform (ONAP) have been presented, along with different deployment models and architectural alternatives.

Architecture-Based Behavioral Adaptation with Generated Alternatives and Relaxed Constraints

Software systems are increasingly required to autonomously adapt their architectural structures and/or behaviors to runtime environmental changes. However, existing architecture-based self-adaptation approaches mostly focus on structural adaptations within a predefined space of architectural alternatives (e.g., switching between two alternative services) while merely considering quality constraints (e.g., reliability and performance). In this paper, we propose a new architecture-based self-adaptation approach, which performs behavioral adaptations with automatically generated alternatives and supports relaxed functional constraints from the perspective of business value. Specifically, we propose a technique to automatically generate behavioral alternatives of a software system from the currently-employed architectural behavioral specification. We employ business value to comprehensively evaluate the behavioral alternatives while capturing the trade-offs among relaxed functional and quality constraints. We also introduce a genetic algorithm-based planning technique to efficiently search for the optimal (sometimes a near-optimal) behavioral alternative that can provide the best business value. The experimental study on an online order processing benchmark has shown promising results that the proposed approach can improve adaptation flexibility and business value with acceptable performance overhead.

끄루찌꼬프의 “플라잉 시티”와 건축적 상상 : 소비에트 미래 도시 계획 프로젝트

This study investigates the ‘Future City’, a unique plan and design of Krutikov in the 1920s of Soviet. The future city plan of Krutikov is discussed in the context of urban development plans in the 20s and 30s. And we analyze the mobility of architecture in Flying City, in focusing the problem of mobility, dynamics, and flexibility in relation to social housing, community dwelling.BR At that time, the architectural alternative of constructivism for production and co-residence is represented by “House-Commune(Дом коммуна)”. Krutikov embodies the transition to socialist collectivism as a mobile architecture, Flying City. The structure of Flying City is divided into House-Commune for a dormitory and an one-person mobile capsule for a personal space.BR This design evolves in the form of the “Town-Commune(Город-коммуна)” for the city of Avtostroi. He tried to solve the social relations of individual space and collective space with system of architectural space. The appearance of fantasy utopia in the design and planning of Flying City is an attempt to realize the social problem of residence through technology.

Protocol Architectures for IoT Domains

In this work we discuss architectural alternatives for the design of a proxy that interconnects IoT domains running CoAP with the rest of the Internet including micro datacenters and other domains building scalable hierarchical architectures. We assume that the CoAP domain is terminated by an IoT proxy with cache, and we investigate several design alternatives, assuming that the proxy autonomously maintains data freshness. Our analysis indicates that multicast and observe-based proxies perform better than the default POST/GET approach in terms of successful data transmission, round trip delay and energy consumption, with the multicast option having a slight advantage.

Interactive multi-objective evolutionary optimization of software architectures

While working on a software specification, designers usually need to evaluate different architectural alternatives to be sure that quality criteria are met. Even when these quality aspects could be expressed in terms of multiple software metrics, other qualitative factors cannot be numerically measured, but they are extracted from the engineers know-how and prior experiences. In fact, detecting not only strong but also weak points in the different solutions seems to fit better with the way humans make their decisions. Putting the human in the loop brings new challenges to the search-based software engineering field, especially for those human-centered activities within the early analysis phase. This paper explores how the interactive evolutionary computation can serve as a basis for integrating the humans judgment into the search process. An interactive approach is proposed to discover software architectures, in which both quantitative and qualitative criteria are applied to guide a multi-objective evolutionary algorithm. The obtained feedback is incorporated into the fitness function using architectural preferences allowing the algorithm to discern between promising and poor solutions. Experimentation with real users has revealed that the proposed interaction mechanism can effectively guide the search towards those regions of the search space that are of real interest to the expert.

URBAN PHOTOVOLTAIC POTENTIAL OF INCLINED ROOFING FOR BUILDINGS IN HERITAGE CENTERS IN EQUATORIAL AREAS

In situ renewable energy production is a favourable alternative for reducing pollution and combating climate change. The research area, Cuenca, Ecuador, is located in the Andes near the equator with optimal conditions for energy self-supply due to its low energy demands and low levels of irradiation variability. In this study, temporary fluctuations in consumption based on 2016 electricity consumption data are characterized. Using GIS, available roofing polygons are obtained, and the amount of usable solar radiation is estimated based on these values. With available surface, orientation, and inclination information, electricity generation based on photovoltaic performance is estimated and compared for monocrystalline silica panels and photovoltaic solar roof tiles, which are architectural alternatives. A potential net supply of 148% is found for monocrystalline silica photovoltaic panels in a typical format, whereas that of photovoltaic tiles is only 61%. In addition, production-demand imbalances are predicted in extreme months and average months and on extreme days due to variations in irradiation and demands.

Architecture alternatives for propane dehydrogenation in a membrane reactor

The main factors affecting the design of a Propane Dehydrogenation Membrane Reactor (PDH MR) are the deactivation of the catalyst and of the membrane due to coking. Both apparently accelerate with increasing temperature or pressure and with depletion of hydrogen; i.e., with conditions that improve conversion in a membrane reactor. Recent studies of this project [Sheintuch et al., 2016; Peters et al., 2016] suggest that pressure should be kept below 5 bar and catalyst temperature should be around 450–500 °C, while the membrane should be kept at 200–250 °C to avoid coking. This favors the distributed reactor design (open architecture) which requires as many as 6 pairs of reactor-separators to achieve the desired 25% conversion with very high sweep to feed ratio (3 for each unit or 18 overall) compared with a single integrated MR that can achieve the same conversion at 450 °C with sweep/feed ratio of 2 or more with counter-current flow. Both designs will yield good selectivity but the catalyst life time is predicted to be ∼2 days while the membrane life time will be shorter in the integrated design as opposed to a stable activity in a cool (250 °C) separator.A new integrated design with an internal gradient is suggested combining the advantages of both approaches. It is based on a three cylindrical zones reactor with catalyst in the outer layer, maintained at 450 °C, permeate in the inner with sweep fed at 250 °C, separated by an inert insolating layer. Initial calculations showed promising results.

Analyzing the impact of system architecture on the scalability of OLTP engines for high-contention workloads

Main-memory OLTP engines are being increasingly deployed on multicore servers that provide abundant thread-level parallelism. However, recent research has shown that even the state-of-the-art OLTP engines are unable to exploit available parallelism for high contention workloads. While previous studies have shown the lack of scalability of all popular concurrency control protocols, they consider only one system architecture---a non-partitioned, shared everything one where transactions can be scheduled to run on any core and can access any data or metadata stored in shared memory. In this paper, we perform a thorough analysis of the impact of other architectural alternatives (Data-oriented transaction execution, Partitioned Serial Execution, and Delegation) on scalability under high contention scenarios. In doing so, we present Trireme, a main-memory OLTP engine testbed that implements four system architectures and several popular concurrency control protocols in a single code base. Using Trireme, we present an extensive experimental study to understand i) the impact of each system architecture on overall scalability, ii) the interaction between system architecture and concurrency control protocols, and iii) the pros and cons of new architectures that have been proposed recently to explicitly deal with high-contention workloads.

Analyzing the impact of system architecture on the scalability of OLTP engines for high-contention workloads

Main-memory OLTP engines are being increasingly deployed on multicore servers that provide abundant thread-level parallelism. However, recent research has shown that even the state-of-the-art OLTP engines are unable to exploit available parallelism for high contention workloads. While previous studies have shown the lack of scalability of all popular concurrency control protocols, they consider only one system architecture---a non-partitioned, shared everything one where transactions can be scheduled to run on any core and can access any data or metadata stored in shared memory. In this paper, we perform a thorough analysis of the impact of other architectural alternatives (Data-oriented transaction execution, Partitioned Serial Execution, and Delegation) on scalability under high contention scenarios. In doing so, we present Trireme, a main-memory OLTP engine testbed that implements four system architectures and several popular concurrency control protocols in a single code base. Using Trireme, we present an extensive experimental study to understand i) the impact of each system architecture on overall scalability, ii) the interaction between system architecture and concurrency control protocols, and iii) the pros and cons of new architectures that have been proposed recently to explicitly deal with high-contention workloads.

Architectural Modelling of Alternatives for Verification of New Interventions on the Example of the Romanesque Palace at Spiš Castle in Slovakia

The article presents the results of the first phase of the research project SK-VEGA 1/0951/16 on using transparent and translucent structures in historical buildings. The team of researchers from the Faculty of Architecture SUT Bratislava introduces possibilities of using lightweight roofs on the model example of a dominant medieval ruin (Romanesque Palace, Spiš Castle, UNESCO site). Architectural 3D-modelling of alternatives gains new methodical importance in conditions, when in real practice only safeguarding conservation approaches are preferred. Research based on design serves as a tool for decision-making on further restoration approaches to a specific cultural heritage object. The selected Romanesque Palace of the Spiš Castle has passed through many structural periods. The interior doesn’t exist and the perimeter walls create a raised landscape landmark. Romanesque, gothic and renaissance periods were identifiable. It would be possible to reconstruct these periods partially hypothetically on the basis of saved archive materials. Inner structures and the roofing of the palace were in individual historical periods changed. Exact frame models of a new roofing were created on the principle of hypothetical reconstruction: from the indication of the medieval form, renaissance form until contemporary new forms respecting the present day horizontal palace’s topping. The aim of the first stage of the research was to present a few architectural alternatives of the roof structure refilling according to the given cultural heritage determinants and structural possibilities. We introduce 12 solutions in graphic and text, which present architectural models of a new roofing, covering the interior by transparent structure based on glass panels and translucent structures based on a textile membrane. We achieve a new space for new functional use of the palace by means of various ways of physical enclosing. On the other side, we work with alternatives of the perimeter wall perforation according to the historical periods. New inserted structures are designed in contemporary technologies and materials. An analysis of particular architectural proposals is the result. The shape, material selection (steel, timber), roof support structure selection and choice of transparent or translucent covering are subordinated to the architectural concept of the historical period’s presentation including contemporaneousness. The solved problem was, how new interventions are able to visually coexist with historical original without diminishing its authenticity. Glazed and membrane structures used for covering authentic ruins request professional architectural modelling of alternatives based on exact historical facts. The decision making process is made easier by visualizations. Structural shapes issued from original tectonic rules (standard, order) appear from the point of visual and also monument restoration criteria more favourable than structural shapes, which were not inspired by these rules. Plane shaped glazed roof shapes from this point of view seem to be more intrinsic than rounded. On the other side, alternatives with use of textile membranes have soft shape morphology, which is beneficial for new and also historic shapes of roofing in this researched example.

Architecting Feasible Deployment Alternatives for Publish-Subscribe Systems

Publish-Subscribe is one of the important patterns for developing scalable distributed systems. Usually, the deployment of the publishers and subscribers to the nodes can be done in many different ways, whereby each deployment alternative will have a different impact on the performance. The many possible architecture design alternatives tend to trade-off with respect to execution cost and communication cost. Unfortunately, for the human engineer it is not tractable to define a feasible configuration in case of large number of nodes and participants. In this paper we propose a generic method to assist the architect by automatically deriving feasible deployment alternatives of Publish-Subscribe based distributed systems. The approach is based on the so-called capacitated task allocation problem (CTAP) in which constraints on memory capacity and processing power are applied to manage the trade-offs between the total execution cost and total communication cost to derive feasible design alternatives. The method is supported by our tool framework (Deploy-PS) that provides an integrated development environment for modeling the Publish-Subscribe deployment architecture, modeling the physical resources and the performance requirements, and the selection and generation of the feasible deployment architecture alternatives.

Network Connectivity Proxy: Architecture, Implementation, and Performance Analysis

Several studies in the last decade have pointed out that many devices, such as computers, are often left powered on even when idle, just to make them available and reachable on the network, leading to large energy waste. The concept of network connectivity proxy (NCP) has been proposed as an effective means to improve energy efficiency. It impersonates the presence of networked devices that are temporally unavailable, by carrying out background networking routines on their behalf. Hence, idle devices could be put into low-power states and save energy. Several architectural alternatives and the applicability of this concept to different protocols and applications have been investigated. However, there is no clear understanding of the limitations and issues of this approach in current networking scenarios. This paper extends the knowledge about the NCP by defining an extended set of tasks that the NCP can carry out, by introducing a suitable communication interface to control NCP operation, and by designing, implementing, and evaluating a functional prototype.

“Tropical” Architecture in the Highlands of Southeast Asia: Tropicality, Modernity and Identity

The “tropical” condition has long been established as a Western trope that defines the “otherness” of climates perceived as hot, humid and uncomfortable compared to the “temperate” West. Both colonial adaptations and “Tropical Modernist” architectural responses to Southeast Asian locations were primarily framed in terms of their amelioration of this apparently hostile environment. That the more recent conflations of tropicality with postcolonial Asian identity and environmental sustainability remain within the same construct leads to questions not only of what architectural alternatives there might be, but also what alternative tropicalities there might be. This paper explores the possibilities suggested by contemporary buildings in Southeast Asia’s tropical highlands. Produced in the relative absence of “tropical” imperatives and the presence of long-standing traditions of autonomy and resistance to lowland state formations, this architecture offers a less homogenous reading of tropicality.

Multi-objective exploration of architectural designs by composition of model transformations

Designing software architectures and optimizing them based on extra-functional properties (EFPs) require to identify appropriate design decisions and to apply them on valid architectural elements. Software designers have to check whether the resulting architecture fulfills the requirements and how it positively improves (possibly conflicting) EFPs. In practice, they apply well-known solutions such as design patterns manually. This is time-consuming, error-prone, and possibly sub-optimal. Well-established approaches automate the search of the design space for an optimal solution. They are based model-driven engineering techniques that formalized design decisions as model transformations and architectural elements as components. Using multi-objective optimizations techniques, they explore the design space by randomly selecting a set of components and applying to them variation operators that include a fixed set of predefined design decisions. In this work, we claim that the design space exploration requires to reason on both architectural components as well as model transformations. More specifically, we focus on possible instantiations of model transformations materialized as the application of model transformation alternatives on a set of architectural components. This approach was prototyped in RAMSES, a model transformation and code generation framework. Experimental results show the capability of our approach (i) to combine evolutionary algorithms and model transformation techniques to explore efficiently a set of architectural alternatives with conflicting EFPs, (ii) to instantiate, and select transformation instances that generate architectures satisfying stringent structural constraints, and (iii) to explore design spaces by chaining more than one transformation. In particular, we evaluated our approach on EFPs, architectures, and design alternatives inspired from the railway industry by chaining model transformations dedicated to implement safety design patterns and software components allocation on a multi-processor hardware platform.