Hub Concept Research Articles

On Decisive Storage Parameters for Minimizing Energy Supply Costs in Multicarrier Energy Systems

Energy storage is one possibility to cope with increasing fluctuating renewable generation in power systems. Especially when considering a number of different energy carriers, synergies enable a reduction in energy supply costs and an increase in operational flexibility. However, the devices have to be selected carefully since installation and operation are generally costly. This paper examines the influence of storage capacity and prediction horizon on the cost optimal multienergy supply of a single-family house and a network of three interconnected houses. Similarities and differences of the two cases are assessed. The energy hub concept is chosen to model the conversion and storage of the energy carriers electricity, gas, and heat. Then, model predictive control is applied to determine the cost optimal control strategy of the available conversion and storage technologies. The results show that storage capacity and the selection of the prediction horizon strongly depend on each other, both in the case of private customers and interconnected houses. Thereby, the prediction horizon is more crucial as it determines the amount of available information to operate the storage devices optimally.

A Formal Framework for Strategic Representations and Conceptual Reorganization

In this paper, we introduce a formal language for modeling the structure of strategic representations and operations that conceptualize change on basis of them. Strategic representations are lower dimensional representations of the world, that underlie the understanding of what business environments are, how they may change, and attempts to shape them. We start from discussing known strategic representations like Porter's five forces model or the strategy canvas. We elicit the conceptual structure underlying these representations by capturing them in our formal language. We demonstrate that our formal language can express operations of conceptual change of strategies such as stretching (the extension of value ranges), lifting (deleting dimensions), extending (adding dimensions), amalgamation (enabling new combinations of features by amalgamating different domains), and transferring structure (exploring analogies). These operations can be the basis for strategizing: for seeing possible reorganizations of strategies and even to become aware of new opportunities. We apply these operations to explain classical business cases, including a detailed study of the conceptual structure underling Steve Jobs' digital hub concept. Our formal language is, to our knowledge, the first attempt to capture the variety of conceptual operations underlying strategic change using one comprehensive model.

РЕГИОНАЛЬНЫЕ ТРАНСПОРТНО-ПЕРЕСАДОЧНЫЕ УЗЛЫ И ИХ ПЛАНИРОВОЧНОЕ РЕШЕНИЕ (НА ПРИМЕРЕ г. МАЦУМОТО, ЯПОНИЯ)

The article deals with the planning concept of transport interchange hubs providing trans-regional bus transportation. According to the ever growing passenger traffic and the number of spatial planning documents, trans-regional bus route networks develop very rapidly in Russia. The findings of the poll of passengers demonstrate their high loyalty to trans-regional bus transportation networks due to their convenient arrangement and little time expenditures (compared to other means of transport). However, little attention is driven by specialized domestic sources to the planning concepts of transport interchange hubs having bus terminals within their structure; the regulatory documentation is missing. One of feasible ways to resolve the issue is to study the international practice of design and construction of transport interchange hubs having bus terminals as the key points providing trans-regional bus transportation.In this article, the transport interchange hub of Matsumoto, Japan, serves as the sample. The author considers its composition and functional site division. The author also performs a detailed analysis of the main elements of the hub, including the design of its pedestrian routes ensuring its functional and spatial unity. Moreover, the author considers the planning structure of a bus terminal and arrangement of retail trade facilities and service areas inside it.

Reviewing the Justice and Security Hub Modality as Piloted in Liberia

‘The Republic of Bangui’ or ‘the Republic of Monrovia’ are phrases we sometimes hear from practitioners to describe post conflict countries where very few services exist outside the capital city. This is especially the case for security – the critical public good in post conflict countries. In response to the need to bring security services closer to the citizens who often need them most, the Government of Liberia and the United Nations are piloting a new approach financed by the UN Peacebuilding Fund (PBF) – the so-called ‘Justice and Security Hubs’. The donor community and the United Nations are watching closely. If this works, there is indication from UN officials that the model could potentially be replicated in other settings such as the East of the Democratic Republic of the Congo (DRC), Haiti and the northern states of South Sudan. If the hub concept is capable of being adapted and successful elsewhere, the United Nations will not only have added a new instrument to its peacekeeping toolkit but will also firmly demonstrate how the UN Peacebuilding Fund can in essence be catalytic in fostering long-term and comprehensive approaches to peacebuilding. This practice note outlines the process of developing and constructing the first hub in Liberia, which is due to be partly operational by the end of 2012, and provides a prognosis on its chances for success.

La calidad de los hubs de América Latina

La medición de la calidad de los hubs, es una tarea que se encuentra en pleno desarrollo con importantes innovaciones que se fueron sucediendo en los últimos años. Sin embargo, el estudio basado en América Latina, exige de ciertas calibraciones en las metodologías más aceptadas, por las propias particularidades del mercado aerocomercial de la región analizada. En este sentido, se retoman las consideraciones básicas respecto al concepto hub, que son útiles para la correcta interpretación de un término que cuenta con acepciones variadas. El objetivo es hacer un análisis comparativo de la calidad de los hubs, estudiando la concentración temporal de las operaciones, en base a las conexiones indirectas realizadas por una misma línea aérea. Los resultados de esta medición, realizada sobre un total de 60 hubs latinoamericanos, muestran que no es posible trazar vinculaciones directas o tendencias generales respecto a indicadores de calidad operativa de hubs.

Expert Discovery and Interactions in Mixed Service-Oriented Systems

Web-based collaborations and processes have become essential in today's business environments. Such processes typically span interactions between people and services across globally distributed companies. Web services and SOA are the defacto technology to implement compositions of humans and services. The increasing complexity of compositions and the distribution of people and services require adaptive and context-aware interaction models. To support complex interaction scenarios, we introduce a mixed service-oriented system composed of both human-provided and Software-Based Services (SBSs) interacting to perform joint activities or to solve emerging problems. However, competencies of people evolve over time, thereby requiring approaches for the automated management of actor skills, reputation, and trust. Discovering the right actor in mixed service-oriented systems is challenging due to scale and temporary nature of collaborations. We present a novel approach addressing the need for flexible involvement of experts and knowledge workers in distributed collaborations. We argue that the automated inference of trust between members is a key factor for successful collaborations. Instead of following a security perspective on trust, we focus on dynamic trust in collaborative networks. We discuss Human-Provided Services (HPSs) and an approach for managing user preferences and network structures. HPS allows experts to offer their skills and capabilities as services that can be requested on demand. Our main contributions center around a context-sensitive trust-based algorithm called ExpertHITS inspired by the concept of hubs and authorities in web-based environments. ExpertHITS takes trust-relations and link properties in social networks into account to estimate the reputation of users.

Redefining of the Rijeka Railway Junction

This paper presents and analyses the redefined Rijeka railway junction. The redefined concept of the Rijeka railroad hub in the context of port and railway interdependence dictates the need to find the accommodation of cargo transport to peripheral locations such as: Krasica, Kukuljanovo, Bakar, Ivani, Bršica and capacity for the island of Krk, while passenger transport would be implemented in the urban area. The most important projects related to Rijeka rail transport system are the construction of a new line of high efficiency between Zagreb and Rijeka, and a new railroad through the tunnel of Učka which will link the ports of Rijeka, Koper and Trieste. Together with the reconstruction of cargo stations Rijeka and Brajdica, an extension of the other tracks on the railroads Škrljevo-Rijeka and Rijeka-Opatija/Matulji should be performed as well as the construction of Krasica, Ivani, Tijani and Vrgljevo stations. The construction includes a multipurpose bridge to the Island of Krk and a railway line to the new container terminal as well as the new railway bypass to “elevation 200”. KEY WORDS: Rijeka railway junction, railway transport system, railway transport, Port of Rijeka

The “extended building energy hub”: A new method for the simultaneous optimization of energy demand and energy supply in buildings

This article deals with simultaneous optimization of building energy performance from both the building and system design points of view. Most research conducted on building energy demand reduction and energy supply optimization treats the demand and supply aspects separately. First, the demand side parameters are analyzed for a demand reduction and then the most suitable configuration for the primary energy conversion is investigated. The relationship between the building energy demand and supply may not be clearly understood when they are analyzed sequentially instead of simultaneously. This article investigates the potentiality of an integrated building demand-supply energy optimization method that could provide a solution to the building energy efficiency problem. The method is based on the Extended Building Energy Hub (EBEH) concept, which is an evolution of the Building Energy Hub (BEH) method. In the BEH approach, the vector of energy inputs—the energy supply—is related to the vector of energy outputs—the energy demand—by means of a coupling matrix. The coefficients of this matrix are functions of the efficiency of the various energy conversion systems and of the distribution of energy fluxes in the energy converters. In the EBEH method, the demand side building design parameters are also included in a coupling matrix and are evaluated together with primary energy options. In this way, for example, the demand side parameters (U values, window-to-wall ratio, etc.) can be contrasted with the opportunity of using solar energy for the production of electricity, and the optimum configuration can be calculated by maximizing the primary energy savings. The article introduces the basic principles of this approach. A preliminary practical demonstration is also developed through the application of a simplified procedure to a case study of an existing building.

Getting ready for carbon capture and storage through a ‘CCS (Carbon Capture and Storage) Ready Hub’: A case study of Shenzhen city in Guangdong province, China

China has been building approximately 1 GW of new coal-fired power plant per week since 2005. Power plants now in construction may continue to operate until 2040. “CCS (Carbon Capture and Storage) Ready” enables and eases the subsequent retrofitting of a plant to be able to capture carbon dioxide later in that plant’s lifetime. Building on the definitions of the IEA GHG (IEA Greenhouse Gas Programme) and GCCSI (Global Carbon Capture and Storage Institute), this study suggests a novel concept ‘CCS Ready Hub’ for implementing CCS Ready. A CCS Ready Hub not only includes a number of new coal-fired power plants but also integrates other existing stationary carbon dioxide emissions sources into the planning for potential infrastructure. We conducted a case study of Guangdong province in China with a detailed engineering and economic assessment in Shenzhen City. The study first reviewed the potential storage sites and analysed the existing stationary emissions sources in Guangdong using a GIS (Geographic Information System) approach. Thereafter, we focused on investigating the economic benefits of a ‘CCS Ready Hub’ at a potential 4 GW new USCPC (ultra-supercritical pulverised coal-fired) power plant in Shenzhen. Using the cost of carbon dioxide avoidance in 2020 as a criterion, we found that the concept of a CCS Ready Hub to finance CCS Ready at a regional planning level rather than at an individual plant is preferred since it significantly reduces the overall cost of building an integrated CCS system to reduce carbon emissions in the future.

부산국제금융센터 해양특성화 개발방안 연구

정부의 금융중심지 조성과 발전에 관한 법률에 따라 부산문현혁신지구에 새롭게 조성될 금융중심지는 기존 금융중심지와 차별화되어 해양특성을 반영한 금융집적지로서 비즈니스 중심지와 연계될 때 국제적 경쟁력을 확보할 수 있다. 본 연구는 금융중심지 개념, 유형 성립여건, 경쟁력 및 해외 사례고찰의 시사점을 통해 개발여건과 관련계획을 분석하여 부산국제금융센터의 국제적 경쟁력은 시민공원 및 북항재개발지구가 연계된 해양특성화에 있음을 제시하고, 관련된 육성 프로그램의 보완방향, 물리적 개발방향, 전략 및 지침을 포함한 개발방안을 제시한다. According to financial hub related law of government, new financial hub in Busan will be differentiated from existing other financial hubs by reflecting regional characteristics as financial cluster and by connecting with business hub. Based on an ongoing busan international finance center in Munhyun innovation city. this study is focused on suggesting development methodes for international competitiveness of Busan international finance center considering of maritime-specialization connecting with citizen park and busan north port renewal districts. through the financial hub concept, types, be valid conditons, competitiveness and international case studies over the analysis of development conditions and a development plans for developing fosterage-programs suppementary and strategy, guidelines of physical developmentde direction.

The pursuit of hubbiness: Analysis of hubs in large multidimensional networks

Abstract Hubs are highly connected nodes within a network. In complex network analysis, hubs have been widely studied, and are at the basis of many tasks, such as web search and epidemic outbreak detection. In reality, networks are often multidimensional, i.e., there can exist multiple connections between any pair of nodes. In this setting, the concept of hub depends on the multiple dimensions of the network, whose interplay becomes crucial for the connectedness of a node. In this paper, we characterize multidimensional hubs. We consider the multidimensional generalization of the degree and introduce a new class of measures, that we call Dimension Relevance, aimed at analyzing the importance of different dimensions for the hubbiness of a node. We assess the meaningfulness of our measures by comparing them on real networks and null models, then we study the interplay among dimensions and their effect on node connectivity. Our findings show that: (i) multidimensional hubs do exist and their characterization yields interesting insights and (ii) it is possible to detect the most influential dimensions that cause the different hub behaviors. We demonstrate the usefulness of multidimensional analysis in three real world domains: detection of ambiguous query terms in a word–word query log network, outlier detection in a social network, and temporal analysis of behaviors in a co-authorship network.

Defining maritime logistics hub and its implication for container port

Since the hub-and-spoke concept was introduced to the aviation market after the US airline deregulation in the late 1970s, it becomes a primary distribution model employed by leading international logistics companies. This pattern drives the companies to consolidate shipments on the large scale at major terminals (i.e. hub) and to redistribute the smaller scale of shipments to their respective destinations via radial links (i.e. spoke). In the field of logistics and supply chains, however, the hub concept has been often introduced in various terms in accordance with functionality: for example, logistics centre, logistics zone, freight terminal, distribution centre and warehouse. Such a heterogeneous terminology on the concept of logistics hub seems still in usage by practitioners and academics alike. Having recognised this rather ambiguous concept and definition in the literature, this article attempts to define the concept applicable to the maritime industry by synthesising existing studies/perspectives and examine its possible implications.

Multiple-Energy Carriers: Modeling of Production, Delivery, and Consumption

This paper presents a generic framework for the modeling of energy systems comprising multiple-energy carriers, such as electricity, heat, gas, biomass, etc. The modeling framework is based on the so-called energy hub approach. The core idea of the energy hub is the definition of a conversion matrix capable of describing the interactions of production, delivery, and consumption in multiple-energy carrier systems. Based on the energy hub concept a broad spectrum of modeling extensions and applications is presented, such as a multiple-energy carrier optimal power flow, risk management and investment analysis tools, agent-based control schemes for decentralized generation units as well as the possibility to analyze the influence of plug-in hybrid electric vehicles (PHEVs) on future energy systems. The paper is concluded with a section presenting the key benefits of the energy hub modeling framework, followed by a discussion on the main design principles generality, scalability, and modularity as well as a discussion on the possibility to follow top-down or bottom-up modeling strategies.

Managing Value in Supply Chain – Case Studies on the Sourcing Hub Concept

In this paper, we postulate that a firm's sourcing knowledge can be a strategic resource for the firm, and explore how firms can capture and build on their sourcing knowledge. We examine the sourcing experiences of four firms in four different countries in the automotive industry, who are in the process of improving their supply-chain partnerships. We study upstream sourcing of these firms: their suppliers and their suppliers' suppliers, and focus on identifying the sourcing knowledge and sourcing cost related parameters with appropriate theoretical explanations. Synthesizing the learnings from these case studies, we propose the concept of the Sourcing Hub, a collaborative center involving the firm, its suppliers and raw material suppliers, as the principal alignment mechanism for managing value in upstream sourcing. Our research shows that deploying a sourcing hub can help firms create value by better management of upstream sourcing related knowledge and costs.

Modelling and analysis of Canadian Forces RSOM-hub locations for Northern operations

This article presents an analysis of Reception, Staging and Onward Movement hub (RSOM-hub) concept to support Canadian Forces (CF) Northern operations and provides insights into the optimal RSOM-hub locations. RSOM-hubs are permanent or temporary staging bases for cross-loading between strategic and tactical lift during military deployment and sustainment operations. Performance measures were developed to assess the effectiveness and the responsiveness of the RSOM-hub concept. A simulation-based optimization model was also developed to determine the optimal number and locations of RSOM-hubs. The model was considered in a multi-objective framework and solution trade-offs were determined through an exhaustive search methodology. Optimal RSOM-hub locations were investigated for different numbers of RSOM-hub solutions. Sensitivity analysis was conducted to examine the impact of different operational parameters on RSOM-hub performance and optimal locations. The study indicated that the RSOM-hub concept could offer potential cost avoidance and response time reduction on deployment lift for Northern operations and could be a potential strategy for improvement of the CF domestic support capability.

Hubs and bottlenecks in plant molecular signalling networks

Conditional control of plant cell function and development relies on appropriate signal perception, signal integration and processing. The development of high throughput technologies such as proteomics and interactomics has enabled the identification of protein interaction networks that mediate signal processing from inputs to appropriate outputs. Such networks can be depicted in graphical representations using nodes and edges allowing for the immediate visualization and analysis of the network's topology. Hubs are network elements characterized by many edges (often degree grade k ≥ 5) which confer a degree of topological importance to them. The review introduces the concept of networks, hubs and bottlenecks and describes four examples from plant science in more detail, namely hubs in the redox regulatory network of the chloroplast with ferredoxin, thioredoxin and peroxiredoxin, in mitogen activated protein (MAP) kinase signal processing, in photomorphogenesis with the COP9 signalosome, COP1 and CDD, and monomeric GTPase function. Some guidance is provided to appropriate internet resources, web repositories, databases and their use. Plant networks can be generated from existing public databases and this type of analysis is valuable in support of existing hypotheses, or to allow for the generation of new concepts or ideas. However, intensive manual curating of in silico networks is still always necessary.

A model to design and optimize multi-energy systems in buildings at the design concept stage

Increasing interest is currently being addressed to multi-energy systems in buildings. These systems integrate different energy sources, at least one of which is renewable, in order to cover the thermal and electrical loads of a building. Since the design and operation of such systems are very complicated for many reasons (e.g. the intermittent nature of the renewable sources, the highly interlinked system layouts), it is of the foremost importance to provide tools to help select the best system configuration and energy sources mix. A modelling approach to multi-energy systems in buildings, based on the energy hub concept is presented in this work. This approach allows the coupling between the energy demand and the energy supply in a building to be modelled in a synthetic way. The model was customised to be used at the concept stage of the building design, either as a system simulation tool or as a system selection tool. If the prices and the characteristics of the energy converters and of the energy-wares are known, it is possible, with a certain set of constraints, to determine the configuration that minimises the initial investment costs, the use of non-renewable sources or the life-cycle costs. This approach makes it possible to avoid the simulation and ranking of a set of different system configurations, and also permits the study of the behaviour of such systems in an open configuration and not as individual systems. An application of the methodology to a case study is provided.

Identifying Hubs in Protein Interaction Networks

BackgroundIn spite of the scale-free degree distribution that characterizes most protein interaction networks (PINs), it is common to define an ad hoc degree scale that defines “hub” proteins having special topological and functional significance. This raises the concern that some conclusions on the functional significance of proteins based on network properties may not be robust.MethodologyIn this paper we present three objective methods to define hub proteins in PINs: one is a purely topological method and two others are based on gene expression and function. By applying these methods to four distinct PINs, we examine the extent of agreement among these methods and implications of these results on network construction.ConclusionsWe find that the methods agree well for networks that contain a balance between error-free and unbiased interactions, indicating that the hub concept is meaningful for such networks.

Multiobjective electric distribution system expansion planning using hybrid energy hub concept

This paper presents a novel approach for optimal electric distribution system expansion planning (OEDSEP) using a hybrid energy hub concept. The proposed method uses an energy hub model to explore the impacts of energy carrier systems on OEDSEP procedure. This algorithm decomposes the OEDSEP problem into three subproblems to achieve an optimal expansion planning of a system in which the investment and operational costs are minimized, while the reliability of the system is maximized. The algorithm was successfully tested in the present research for an urban distribution system.

The Strategic Hub Concept: Plan C for Iraq?

This article will apply what shall be termed a “strategic hub” concept of counterinsurgency to the war in Iraq. This concept posits that the development of insurgent and militia nodes or “hubs” of activity could provide a more relevant way to address the key dilemmas of the Iraq equation in light of the Coalition and Iraq government's inability to secure Iraq. The article will argue that ceding the insurgency and militias ground on a temporary basis may be required to maintain both military and political momentum in the post “surge” Iraq given the draw down of U.S. forces, the immaturity of the Iraqi Security Forces, and the present state of American and Iraqi politics.