Virtual Single Network Path by Integrating Multiple and Heterogeneous Challenged Networks

Motivated by the question of how to quickly transfer large files if multiple and heterogeneous networks are available but each has insufficient performance for a requested task, we propose a data transfer framework for integrating multiple and heterogeneous challenged access networks, in which long delays, heavy packet losses, and frequent disconnections are observed. An important feature of this framework is to transmit the control information separately from the transmission of data information, where they are flexibly transferred on different types of communication media (network paths) in different ways, and to provide a virtual single network path between the two nodes. We describe the design of the mechanisms of this framework such as the retransmission, the rate adjustment of each data flow, and the data-flow setup control. We validate a prototype implementation through two different experiments using terrestrial networks and a satellite communication system

VERTICAL INTEGRATION FOR FULL OUTSOURCING: GROWTH AND INTERNATIONALIZATION OF A PORTUGUESE PACKAGING FIRM

Based on a case study of a Portuguese packaging firm, this paper examines how vertical integration of the supplier serves as a vehicle for the full outsourcing of the client firms' needs in a solution that reduces transaction costs, favors specialization, and permits small and mediumsized firms to develop competencies that may be exploited in a wide array of projects. Vertical integration by the supplier (a governance decision) is a strategic response to changes in the sourcing model of the clients. Client-supplier relationships have inter-spatial and inter-temporal value that surpasses spot market exchanges.strategic outsourcing, vertical integration, internationalization, case study

Ambidexterity of design management in different approaches to digital design:review of organizational attitudes in the East and the West in new product development process

Currently, there is growing interest in shaping a digital ecosystem that embraces holistic design approaches. In the digital realm, organizational approaches to managing design are required to shift to ‘designing’ towards holistic digital design, rather than ‘design’ for a completed output. Within this context, this paper reviews how organizational cultures can impact the development of holistic product design in competitive digital landscapes. This is done by investigating different organizational cultures as reflected in large Eastern and Western organizations’ approaches to managing design in the new product development (NPD) process. Despite significances of ‘designing’ this study discovered ambidexterity aspects of digital design in NPD projects, from international organizational perspectives. The findings offer key understandings that can explain the dilemmatic relations by examining key differences of design priorities in new digital product development in the East and the West: namely the East focusing on ‘design output’; whereas the West expecting ‘design outcomes’. Based on this we propose two major scenarios that represent the different approaches to managing design by organizational cultures

Systemic Innovation in a Distributed Network Paradox or Pinnacle?

Previous research has suggested that there is a dichotomy of organisational practices: companies involved in autonomous or modularised innovations, it is argued, benefit from decentralised approaches where coordination primarily takes place through the marketplace, whereas the benefits of systemic innovation are said to be appropriated best by centralised organisations. However, case studies of subcontractors to the Danish wind turbine industry suggest that the ability to meet heterogeneous demands plays an important role for the success of different forms of organisational practices in relation to innovation. The modularised versus systemic architecture approach therefore appears to be a too sweeping dichotomy for describing what can better be perceived as an array of different practices for balancing innovation contribution with the ability of individual firms to appropriate innovation benefits – and a heterogeneous market perception is a core element in building and sustaining this ability.Organisational Forms, Innovation System, Knowledge Complementarities, Value Appropriation

Gunrock: A High-Performance Graph Processing Library on the GPU

For large-scale graph analytics on the GPU, the irregularity of data access and control flow, and the complexity of programming GPUs have been two significant challenges for developing a programmable high-performance graph library. "Gunrock", our graph-processing system designed specifically for the GPU, uses a high-level, bulk-synchronous, data-centric abstraction focused on operations on a vertex or edge frontier. Gunrock achieves a balance between performance and expressiveness by coupling high performance GPU computing primitives and optimization strategies with a high-level programming model that allows programmers to quickly develop new graph primitives with small code size and minimal GPU programming knowledge. We evaluate Gunrock on five key graph primitives and show that Gunrock has on average at least an order of magnitude speedup over Boost and PowerGraph, comparable performance to the fastest GPU hardwired primitives, and better performance than any other GPU high-level graph library.Comment: 14 pages, accepted by PPoPP'16 (removed the text repetition in the previous version v5

Transport layer protocols and architectures for satellite networks

Designing efficient transmission mechanisms for advanced satellite networks is a demanding task, requiring the definition and the implementation of protocols and architectures well suited to this challenging environment. In particular, transport protocols performance over satellite networks is impaired by the characteristics of the satellite radio link, specifically by the long propagation delay and the possible presence of segment losses due to physical channel errors. The level of impact on performance depends upon the link design (type of constellation, link margin, coding and modulation) and operational conditions (link obstructions, terminal mobility, weather conditions, etc.). To address these critical aspects a number of possible solutions have been presented in the literature, ranging from limited modifications of standard protocols (e.g. TCP, transmission control protocol) to completely alternative protocol and network architectures. However, despite the great number of different proposals (or perhaps also because of it), the general framework appears quite fragmented and there is a compelling need of an integration of the research competences and efforts. This is actually the intent of the transport protocols research line within the European SatNEx (Satellite Network of Excellence) project. Stemming from the authors' work on this project, this paper aims to provide the reader with an updated overview of all the possible approaches that can be pursued to overcome the limitations of current transport protocols and architectures, when applied to satellite communications. In the paper the possible solutions are classified in the following categories: optimization of TCP interactions with lower layers, TCP enhancements, performance enhancement proxies (PEP) and delay tolerant networks (DTN). Advantages and disadvantages of the different approaches, as well as their interactions, are investigated and discussed, taking into account performance improvement, complexity, and compliance to the standard semantics. From this analysis, it emerges that DTN architectures could integrate some of the most efficient solutions from the other categories, by inserting them in a new rigorous framework. These innovative architectures therefore may represent a promising solution for solving some of the important problems posed at the transport layer by satellite networks, at least in a medium-to-long-term perspective. Copyright (c) 2006 John Wiley & Sons, Ltd