Osaka University

Displaying 1-40 of 68 results

  • White Papers // Oct 2012

    Perfect Cell Partitioning Scheme for Micro-Cellular Networks

    A Perfect Cell Partitioning (PCP) scheme is described for controlling the transmission power of base stations in a cellular communication system to prevent radio frequency interference among adjacent base stations. A base station using this scheme can use its entire frequency range, while one using the conventional scheme can use...

    Provided By Osaka University

  • White Papers // May 2012

    Secured Energy-Aware Sleep Scheduling Algorithm in Duty-Cycled Sensor Networks

    Sleep scheduling algorithms for duty-cycled sensor networks have received great attention, since sensors should dynamically be awake and asleep to save energy consumption. Among all current sleep scheduling algorithms, only the recently proposed Energy Consumed uniformly-Connected K-Neighborhood (EC-CKN) algorithm focuses on not only the coverage of the resultant network, but...

    Provided By Osaka University

  • White Papers // May 2012

    A Study on Hybrid Optical Network Architecture With OCDM Technology

    Optical Circuit Switching (OCS) technology is mostly used in all-optical network. Most OCS networks use WDM on fibers and one wavelength is assigned to one connection. However, OCS technology needs to pre-configure a light-path before transmitting data, and the pre-configuring overhead takes more than round trip time between the source...

    Provided By Osaka University

  • White Papers // May 2012

    Computing Path Blocking Probabilities for Traffic Splitting in Optical Hybrid Switching Networks

    Recent papers in the literature on hybrid optical architectures combining path and packet switching have shown that it can be a good candidate for future optical networks. However, the optimization of the traffic splitting parameters by some metrics is vital to maximize the benefit by the hybrid architecture. Blocking rate...

    Provided By Osaka University

  • White Papers // May 2012

    A Geographic Routing Oriented Sleep Scheduling Algorithm in Duty-Cycled Sensor Networks

    Geographic routing is assumed to be the most potential routing scheme in Wireless Sensor Networks (WSNs) due to its scalability and efficiency. Recently more and more research work about geographic routing pay attention to its application scenarios in duty-cycled WSNs because of the natural advantage of saving energy consumption with...

    Provided By Osaka University

  • White Papers // Jan 2012

    Trade-Off Between Reliability and Energy Cost for Content-Rich Data Transmission in Wireless Sensor Networks

    In wireless sensor networks, the power of energy-constrained sensor nodes is largely drained by data communication tasks. Designing energy-efficient data communication mechanisms is, therefore, a major key to maximizing the life-time of wireless sensor networks. This challenge is magnified for visual sensor networks, where the collected and transmitted data is...

    Provided By Osaka University

  • White Papers // Sep 2011

    Models of Link Capacity Distribution in ISP's Router-Level Topology

    Modeling the Internet is vital for network researches. Recent measurement studies on the Internet topology show that the degree distribution obeys the power-law distribution. However, only the degree distribution does not determine the performance of network control methods. As previous studies have shown, one of important factors to characterize the...

    Provided By Osaka University

  • White Papers // Sep 2011

    A Modeling Method for Router-Level Topologies Based on Network-Cost Optimization

    Measurement studies of Internet topologies show that the degree distribution of the topologies exhibits a power-law attribute. However, it is apparent that only degree distributions do not determine the structure of ISP topologies, where ISP designs router-level topologies based on their own design policies. Other structural properties than degree distribution...

    Provided By Osaka University

  • White Papers // Aug 2011

    A Smart Access-Point Selection Algorithm for Scalable Wireless Mesh Networks

    As a flexible, cost-efficient solution for a scalable Internet-access network, the authors have studied the architecture and design optimization issues of the Wireless Internet-access Mesh NETwork (WIMNET) that is composed of wirelessly connected multiple Access-Points (APs). WIMNET utilizes two types of APs as wireless mesh routers to achieve the scalability...

    Provided By Osaka University

  • White Papers // Aug 2011

    Geographic Multipath Routing in Duty-Cycled Wireless Sensor Networks: One-Hop or Two-Hop?

    This paper proposes a novel 2-hop geographic multipath routing algorithm TPGFplus in energy consumption balanced duty-cycled WSNs. Analysis and simulation results show that TPGFPlus outperforms previous algorithm TPGF on finding more average number of paths and shorter average lengths of paths, but without causing additional energy consumption. The Connected K-Neighborhood...

    Provided By Osaka University

  • White Papers // Jul 2011

    Data Loss Prevention for Confidential Web Contents and Security Evaluation with BAN Logic

    Since the enforcement of the private information protection law of Japan, protection of confidential information is one of the significant issues in enterprises and organizations. However, many incidents of confidential information leakage occur and this becomes a serious issue in the industrial society. There is no effective countermeasure to prevent...

    Provided By Osaka University

  • White Papers // Jun 2011

    Power ControlMethods for Improving Spatial Reuse in TDMA-BasedWirelessMesh Networks

    Wireless Mesh Networks (WMNs) have attracted a great deal of interest in recent years as a cost-effective method to provide a wireless network infrastructure. To accommodate various types of application traffic in WMNs, improvement of network capacity is one of the most critical issues. The efficiency of wireless network resource...

    Provided By Osaka University

  • White Papers // Jun 2011

    Effect Of ISO Standards On Exports Of Firms In Eastern Europe And Central Asia: An Application Of The Control Function Approach

    Growing number of firms in developing countries have earned certifications such as International Standards Organization (ISO) as it enhances reputation of their company or brand and attract buyers particularly in export market. This paper evaluates the effect of international standards certification on firm's export performance in Europe and Central Asia...

    Provided By Osaka University

  • White Papers // Mar 2011

    Assessing The Impact Of The ASEAN Economic Community

    Consequences of the ASEAN Economic Community (AEC) are investigated using a dynamic Computable General Equilibrium (CGE) model. Quantitative assessments of the effects on economic welfare, trade flows and sectoral output are offered. When the removal of trade barriers are combined with reductions in administrative and technical barriers and lowering the...

    Provided By Osaka University

  • White Papers // Mar 2011

    Design Of A Social Security System: Pension System Vs. Unemployment Insurance

    This paper presents consideration of how the social security system evolves as the attributes of voters change. In the authors' setting, policy determination is based on majority voting. The government has two components of social security policy: a pension system and unemployment insurance. When workers constitute most voters, the pension...

    Provided By Osaka University

  • White Papers // Dec 2010

    Energy-Efficient Receiver-Driven Wireless Mesh Sensor Networks

    A major challenge in wireless sensor networks research is energy efficiency. In the Intermittent Receiver-driven Data Transmission (IRDT) protocol, which aims at saving energy, communication between two nodes commences when multiple receiver nodes transmit their own IDs and the sender nodes receive them. This protocol can be used to construct...

    Provided By Osaka University

  • White Papers // Dec 2010

    On Parameter Tuning of Data Transfer Protocol GridFTP for Wide-Area Networks

    In wide-area Grid computing, geographically distributed computational resources are connected for enabling efficient and large-scale scientific/engineering computations. In the wide-area Grid computing, a data transfer protocol called GridFTP has been commonly used for large file transfers. GridFTP has the following features for solving problems of the existing TCP. First, for...

    Provided By Osaka University

  • White Papers // Dec 2010

    Architectural Design of Unified Multiplex Communications for One-Time Use of IP Addresses

    In the conventional IP network, all servers have a risk against any implicit/explicit attacks from unknown devices because the IP address of the server is fixed during the server is active. In this paper, the authors try to solve the problem by proposing a new communication architecture where a node...

    Provided By Osaka University

  • White Papers // Nov 2010

    Comparison of Packet Switch Architectures and Pacing Algorithms for Very Small Optical RAM

    One of the difficulties with Optical Packet Switched (OPS) networks is buffering optical packets in the network. The research on optical RAM presently being done is not expected to achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization in small...

    Provided By Osaka University

  • White Papers // Nov 2010

    Self Transforming to Power Law Topology for Overlay Networks

    Designing the architecture of future network requires the understanding of how a topological structure influences the performance of a network. The paper of the topology known as complex network theory has revealed the omnipresence of power law topology in many real networks. This power law topology is known to provide...

    Provided By Osaka University

  • White Papers // Nov 2010

    The Effects Of Costly Exploration On Optimal Investment Timing

    This paper investigates a principal-agent model in which an owner (principal) optimizes a contract with a manager (agent) delegated to undertake an investment project. In the model, the authors explore the effects of costly exploration by which the manager learns the real value of development cost. They show that high...

    Provided By Osaka University

  • White Papers // Oct 2010

    An Inter-Networking Mechanism Using Stepwise Synchronization for Wireless Sensor Networks

    To realize the ambient information society, multiple wireless networks deployed in the region or carried by users are required to cooperate with each other. Since duty cycles and operational frequencies are different among networks, the authors need a mechanism to allow networks to efficiently exchange messages. In this paper, they...

    Provided By Osaka University

  • White Papers // Sep 2010

    Retirement And Social Security: A Political Economy Perspective

    Countries with higher implicit taxes on continued work are associated with lower labor force participation rates of the elderly. This paper constructs a politico-economic model that accounts for this feature based on multiple, self-fulfilling expectations of agents. In this model, agents are identical at birth and can become skilled (or...

    Provided By Osaka University

  • White Papers // Aug 2010

    The Political Economy Of Social Security And Public Goods Provision In A Borrowing-constrained Economy

    This paper introduces an overlapping-generations model with earnings heterogeneity and borrowing constraints. The labor income tax and the allocation of tax revenue across social security and forward intergenerational public goods are determined in a bidimensional majoritarian voting game played by successive generations. The political equilibrium is characterized by an ends-against-the-middle...

    Provided By Osaka University

  • White Papers // Jul 2010

    Estimation of Traffic Amounts on All Links by Using the Information From a Subset of Nodes

    Traffic information is required to perform traffic engineering. However, as the network that require traffic engineering becomes large, the overhead to collect the traffic amount information required for traffic engineering becomes large. In this paper, the authors propose a method to reduce the overhead to collect the traffic amount information....

    Provided By Osaka University

  • White Papers // Jun 2010

    A Reaction-Diffusion Based Coding Rate Control Mechanism for Camera Sensor Networks

    A wireless camera sensor network is useful for surveillance and monitoring for its visibility and easy deployment. However, it suffers from the limited capacity of wireless communication and a network is easily overflowed with a considerable amount of video traffic. In this paper, the authors propose an autonomous video coding...

    Provided By Osaka University

  • White Papers // Jun 2010

    Self-Organization Based Network Architecture and Control Technologies for New Generation Networks

    An emerging new generation network is requested to accommodate an enormous numbers of nodes with high diversity and a wide variety of traffic and applications. To achieve higher scalability, adaptability, and robustness than ever before. In this paper, the authors present new network architecture composed of self-organizing entities. The architecture...

    Provided By Osaka University

  • White Papers // Jun 2010

    Adaptive Virtual Network Topology Control in WDM-Based Optical Networks

    Virtual Network Topology (VNT) is one efficient way to transfer the IP packet over the wavelength-routed optical networks. In recent years various new services have emerged, and IP traffic has been highly fluctuated. Therefore, adaptability against changes of traffic is one of the most important characteristics to accommodate the IP...

    Provided By Osaka University

  • White Papers // May 2010

    Dynamics of Feedback-Induced Packet Delay in Power-Law Networks

    Dynamic interactions of various network-related protocols induced by the functional partition make the Internet to be complicated systems; details are hardly captured because of large-scale and heterogeneous structure. One of complex behaviors of the Internet is traffic dynamics. For example, flow control and congestion control performed by end host can...

    Provided By Osaka University

  • White Papers // May 2010

    Trade-Off Evaluation Between Fairness and Throughput for TCP Congestion Control Mechanisms in a Wireless LAN Environment

    Per-flow unfairness of TCP throughput in the IEEE 802.11 wireless LAN environment has been reported. Although a number of researchers have proposed various methods for alleviating the unfairness, they evaluated the fairness of their methods separately from the network bandwidth utilization, meaning that they did not consider the trade-off relationships...

    Provided By Osaka University

  • White Papers // May 2010

    Robustness of Receiver-Driven Multi-Hop Wireless Network With Soft-State Connectivity Management

    Energy saving and ensuring robust data collection are the big subjects in realization of wireless sensor networks. In the Intermittent Receiver-driven Data Transmission (IRDT) protocol, which aims to save energy and get high reliability, communication between nodes commences when multiple receiver nodes transmit their own IDs intermittently and a sender...

    Provided By Osaka University

  • White Papers // May 2010

    Self-Organized Control for Visual Sensor Networks

    A visual sensor network consisting of embedded visual sensor nodes, e.g. wireless cameras, is promising as a monitoring and surveillance system for the high visibility and the amount of information that video images provide. However, it suffers from limitations on the wireless communication capacity and the computational capacity. For the...

    Provided By Osaka University

  • White Papers // Apr 2010

    Error-Tolerant Coverage Control Based on Bio-Inspired Attractor Selection Model for Wireless Sensor Networks

    A coverage problem is one of major issues of a wireless sensor network to prolong the lifetime while guaranteeing that the target region and objects are monitored by sufficient number of active nodes. There have been many proposals on the coverage problem, but most of them use geometric algorithms in...

    Provided By Osaka University

  • White Papers // Apr 2010

    Can The Health Insurance Reforms Stop An Increase In Medical Costs Of Middle- And Old-aged Persons In Japan?

    Using two-period panel data from the Nippon Life Insurance Research Institute, this paper tests the hypothesis that an increase in the self-pay ratio of medical expenditures associated with the Japanese health insurance reforms of April 2003 reduced individual medical costs. The authors find that the increase in the self-pay ratio...

    Provided By Osaka University

  • White Papers // Feb 2010

    Low-Energy-Consumption Ad Hoc Mesh Network Based on Intermittent Receiver-Driven Transmission

    In the ad hoc network, it is considered that mesh structure topology can achieve high communication reliability. However, since the power consumption in an ad hoc network of the mesh configuration becomes large, it is an important research topic to control it. In efforts to develop a method for controlling...

    Provided By Osaka University

  • White Papers // Feb 2010

    The Impact of FQDN Database Updates on Name-Based Routing Architecture

    Sophisticated routing protocols, such as content-based routing, have been studied and proposed to replace Internet Protocol (IP) in the future Internet. Routing based on content will make finding, querying, and retrieving the desired information possible within the routers rather than having the routers forward the packets to data servers or...

    Provided By Osaka University

  • White Papers // Jan 2010

    Energy Efficient Sleep Scheduling in Wireless Sensor Networks Inspired by Satellite Behavior of Frogs

    One of the most challenging research tasks in the field of wireless sensor networks is controlling the power consumption of batteries and prolonging network lifetime. For sensor networks which consist of a large number of sensor nodes, self-organized control is more suitable than centralized control. In particular, research on bio-inspired...

    Provided By Osaka University

  • White Papers // Jan 2010

    A Grid Environment for Data Integration of Scientific Databases

    Effective integration of heterogeneous data sources has been studied as the most pressing challenge in various fields; such as, high energy physics, astronomy, and life sciences. In this talk, authors present a data integration system by using Globus Toolkit with OGSA-DAI. For associating related data among many databases, authors have...

    Provided By Osaka University

  • White Papers // Jan 2010

    Multi-Project Software Engineering: An Example

    In this paper authors present an approach for developers to benefit from multi-project software knowledge. As authors show in this paper, this can be achieved by gathering information about how numerous software projects are being built, and about the interrelation of the modules within the projects. Compared to approaches that...

    Provided By Osaka University

  • White Papers // Jan 2010

    Public Capital, Public Pension, And Growth

    This paper constructs an endogenous growth model with overlapping generations, whose engine of economic growth is productive public capital. The government faces a trade-off in public policy between public investment and social security provision because of its budget constraint. Larger public investment accelerates economic growth. On the other hand, larger...

    Provided By Osaka University

  • White Papers // Jul 2011

    Data Loss Prevention for Confidential Web Contents and Security Evaluation with BAN Logic

    Since the enforcement of the private information protection law of Japan, protection of confidential information is one of the significant issues in enterprises and organizations. However, many incidents of confidential information leakage occur and this becomes a serious issue in the industrial society. There is no effective countermeasure to prevent...

    Provided By Osaka University

  • White Papers // Oct 2012

    Perfect Cell Partitioning Scheme for Micro-Cellular Networks

    A Perfect Cell Partitioning (PCP) scheme is described for controlling the transmission power of base stations in a cellular communication system to prevent radio frequency interference among adjacent base stations. A base station using this scheme can use its entire frequency range, while one using the conventional scheme can use...

    Provided By Osaka University

  • White Papers // Jan 2010

    A Grid Environment for Data Integration of Scientific Databases

    Effective integration of heterogeneous data sources has been studied as the most pressing challenge in various fields; such as, high energy physics, astronomy, and life sciences. In this talk, authors present a data integration system by using Globus Toolkit with OGSA-DAI. For associating related data among many databases, authors have...

    Provided By Osaka University

  • White Papers // Jan 2010

    Multi-Project Software Engineering: An Example

    In this paper authors present an approach for developers to benefit from multi-project software knowledge. As authors show in this paper, this can be achieved by gathering information about how numerous software projects are being built, and about the interrelation of the modules within the projects. Compared to approaches that...

    Provided By Osaka University

  • White Papers // Feb 2009

    Advanced Query Processing in Mobile Ad Hoc Networks

    At the early stage of Mobile Ad hoc NETworks (MANETs) research, most studies focused on routing protocols to support communications among mobile nodes connected to each other by one-hop/multi-hop links. However, in many MANET applications, mobile nodes share data with each other and access data held by other mobile nodes....

    Provided By Osaka University

  • White Papers // May 2009

    Network Virtualization Server for Adaptive Network Control

    This paper considers the virtualization technologies of an optical network infrastructure and the design of related systems. The objective of the research project is to develop a network virtualization server that providing the functionality of virtualizing optical network resources and to demonstrate the network infrastructure accommodating multiple service networks using...

    Provided By Osaka University

  • White Papers // Jul 2009

    Congestion Propagation Among Routers With TCP Flows

    In recent years, various non-linear phenomena of the Internet have been discovered. For instance, it is reported that congestion of a router propagates to neighboring routers like a wave. Several researches on congestion propagation among routers have been performed. However, in these researches, cause of congestion propagation and condition that...

    Provided By Osaka University

  • White Papers // Jun 2009

    Performance Evaluation of Data Transfer Protocol GridFTP for Grid Computing

    In Grid computing, a data transfer protocol called GridFTP has been widely used for efficiently transferring a large volume of data. Currently, two versions of GridFTP protocols, GridFTP version 1 (GridFTP v1) and GridFTP version 2 (GridFTP v2), have been proposed in the GGF. GridFTP v2 supports several advanced features...

    Provided By Osaka University

  • White Papers // Dec 2009

    Global Shocks And The Japanese Economy: Structural Changes In The 1990s

    This paper analyzes how those global shocks as foreign business cycles and exchange rate realignments affect the Japanese economy and whether there are structural changes in the transmission mechanism of these shocks in the recent period by using a VAR model. This paper finds that, since the 1990s the impact...

    Provided By Osaka University

  • White Papers // Jun 2011

    Effect Of ISO Standards On Exports Of Firms In Eastern Europe And Central Asia: An Application Of The Control Function Approach

    Growing number of firms in developing countries have earned certifications such as International Standards Organization (ISO) as it enhances reputation of their company or brand and attract buyers particularly in export market. This paper evaluates the effect of international standards certification on firm's export performance in Europe and Central Asia...

    Provided By Osaka University

  • White Papers // Dec 2008

    A Planner Of Global Income Transfers: International Public Goods And Productivity Differentials

    The purpose of this paper, by introducing the adjustment expense of global income transfers across N countries, is to produce an explicit rule for the planner country regarding income transfers, and to investigate the effects of income transfers on each country's welfare. The findings are: when country i has a...

    Provided By Osaka University

  • White Papers // Feb 2009

    Endogenous Policy Announcement And Accountability For Inflation Target

    In this paper, the author shows that accountability for inflation target will improve social welfare when the central bank makes transparency-opaqueness choices endogenously. The key elements are uncertainty of the firms' informational quality, the opacity bias of constrained discretionary monetary policy under noisy information, and the role of harmful noisy...

    Provided By Osaka University

  • White Papers // Dec 2010

    On Parameter Tuning of Data Transfer Protocol GridFTP for Wide-Area Networks

    In wide-area Grid computing, geographically distributed computational resources are connected for enabling efficient and large-scale scientific/engineering computations. In the wide-area Grid computing, a data transfer protocol called GridFTP has been commonly used for large file transfers. GridFTP has the following features for solving problems of the existing TCP. First, for...

    Provided By Osaka University

  • White Papers // Apr 2010

    Can The Health Insurance Reforms Stop An Increase In Medical Costs Of Middle- And Old-aged Persons In Japan?

    Using two-period panel data from the Nippon Life Insurance Research Institute, this paper tests the hypothesis that an increase in the self-pay ratio of medical expenditures associated with the Japanese health insurance reforms of April 2003 reduced individual medical costs. The authors find that the increase in the self-pay ratio...

    Provided By Osaka University

  • White Papers // Mar 2011

    Assessing The Impact Of The ASEAN Economic Community

    Consequences of the ASEAN Economic Community (AEC) are investigated using a dynamic Computable General Equilibrium (CGE) model. Quantitative assessments of the effects on economic welfare, trade flows and sectoral output are offered. When the removal of trade barriers are combined with reductions in administrative and technical barriers and lowering the...

    Provided By Osaka University

  • White Papers // Sep 2010

    Retirement And Social Security: A Political Economy Perspective

    Countries with higher implicit taxes on continued work are associated with lower labor force participation rates of the elderly. This paper constructs a politico-economic model that accounts for this feature based on multiple, self-fulfilling expectations of agents. In this model, agents are identical at birth and can become skilled (or...

    Provided By Osaka University

  • White Papers // Mar 2011

    Design Of A Social Security System: Pension System Vs. Unemployment Insurance

    This paper presents consideration of how the social security system evolves as the attributes of voters change. In the authors' setting, policy determination is based on majority voting. The government has two components of social security policy: a pension system and unemployment insurance. When workers constitute most voters, the pension...

    Provided By Osaka University

  • White Papers // Aug 2010

    The Political Economy Of Social Security And Public Goods Provision In A Borrowing-constrained Economy

    This paper introduces an overlapping-generations model with earnings heterogeneity and borrowing constraints. The labor income tax and the allocation of tax revenue across social security and forward intergenerational public goods are determined in a bidimensional majoritarian voting game played by successive generations. The political equilibrium is characterized by an ends-against-the-middle...

    Provided By Osaka University

  • White Papers // Jan 2010

    Public Capital, Public Pension, And Growth

    This paper constructs an endogenous growth model with overlapping generations, whose engine of economic growth is productive public capital. The government faces a trade-off in public policy between public investment and social security provision because of its budget constraint. Larger public investment accelerates economic growth. On the other hand, larger...

    Provided By Osaka University

  • White Papers // Nov 2008

    The Sigmoidal Investment Function

    Based on the investment theory of Abel and Eberly (1994), the authors develop an analytical model of adjustment costs, which produces a sigmoidal investment function. They also estimate the piecewise linear investment function, which includes as special cases linear models, models with one threshold, the original model of Abel and...

    Provided By Osaka University

  • White Papers // Nov 2010

    The Effects Of Costly Exploration On Optimal Investment Timing

    This paper investigates a principal-agent model in which an owner (principal) optimizes a contract with a manager (agent) delegated to undertake an investment project. In the model, the authors explore the effects of costly exploration by which the manager learns the real value of development cost. They show that high...

    Provided By Osaka University

  • White Papers // Jul 2009

    The Effects Of A Monetary Policy Shock: Evidence From India

    This paper empirically investigates the transmission of the Reserve Bank of India (RBI)'s monetary policy at a time when multiple indicator approaches are popular, using a structural VAR approach. The authors find that non-recursive zero restrictions must be imposed on the contemporaneous structural parameters to identify a monetary policy shock...

    Provided By Osaka University

  • White Papers // Jun 2011

    Power ControlMethods for Improving Spatial Reuse in TDMA-BasedWirelessMesh Networks

    Wireless Mesh Networks (WMNs) have attracted a great deal of interest in recent years as a cost-effective method to provide a wireless network infrastructure. To accommodate various types of application traffic in WMNs, improvement of network capacity is one of the most critical issues. The efficiency of wireless network resource...

    Provided By Osaka University

  • White Papers // Aug 2011

    A Smart Access-Point Selection Algorithm for Scalable Wireless Mesh Networks

    As a flexible, cost-efficient solution for a scalable Internet-access network, the authors have studied the architecture and design optimization issues of the Wireless Internet-access Mesh NETwork (WIMNET) that is composed of wirelessly connected multiple Access-Points (APs). WIMNET utilizes two types of APs as wireless mesh routers to achieve the scalability...

    Provided By Osaka University

  • White Papers // Sep 2011

    Models of Link Capacity Distribution in ISP's Router-Level Topology

    Modeling the Internet is vital for network researches. Recent measurement studies on the Internet topology show that the degree distribution obeys the power-law distribution. However, only the degree distribution does not determine the performance of network control methods. As previous studies have shown, one of important factors to characterize the...

    Provided By Osaka University

  • White Papers // Sep 2011

    A Modeling Method for Router-Level Topologies Based on Network-Cost Optimization

    Measurement studies of Internet topologies show that the degree distribution of the topologies exhibits a power-law attribute. However, it is apparent that only degree distributions do not determine the structure of ISP topologies, where ISP designs router-level topologies based on their own design policies. Other structural properties than degree distribution...

    Provided By Osaka University

  • White Papers // Nov 2010

    Comparison of Packet Switch Architectures and Pacing Algorithms for Very Small Optical RAM

    One of the difficulties with Optical Packet Switched (OPS) networks is buffering optical packets in the network. The research on optical RAM presently being done is not expected to achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization in small...

    Provided By Osaka University

  • White Papers // May 2010

    Self-Organized Control for Visual Sensor Networks

    A visual sensor network consisting of embedded visual sensor nodes, e.g. wireless cameras, is promising as a monitoring and surveillance system for the high visibility and the amount of information that video images provide. However, it suffers from limitations on the wireless communication capacity and the computational capacity. For the...

    Provided By Osaka University

  • White Papers // Jun 2010

    A Reaction-Diffusion Based Coding Rate Control Mechanism for Camera Sensor Networks

    A wireless camera sensor network is useful for surveillance and monitoring for its visibility and easy deployment. However, it suffers from the limited capacity of wireless communication and a network is easily overflowed with a considerable amount of video traffic. In this paper, the authors propose an autonomous video coding...

    Provided By Osaka University

  • White Papers // Dec 2010

    Energy-Efficient Receiver-Driven Wireless Mesh Sensor Networks

    A major challenge in wireless sensor networks research is energy efficiency. In the Intermittent Receiver-driven Data Transmission (IRDT) protocol, which aims at saving energy, communication between two nodes commences when multiple receiver nodes transmit their own IDs and the sender nodes receive them. This protocol can be used to construct...

    Provided By Osaka University

  • White Papers // Feb 2010

    The Impact of FQDN Database Updates on Name-Based Routing Architecture

    Sophisticated routing protocols, such as content-based routing, have been studied and proposed to replace Internet Protocol (IP) in the future Internet. Routing based on content will make finding, querying, and retrieving the desired information possible within the routers rather than having the routers forward the packets to data servers or...

    Provided By Osaka University

  • White Papers // Apr 2010

    Error-Tolerant Coverage Control Based on Bio-Inspired Attractor Selection Model for Wireless Sensor Networks

    A coverage problem is one of major issues of a wireless sensor network to prolong the lifetime while guaranteeing that the target region and objects are monitored by sufficient number of active nodes. There have been many proposals on the coverage problem, but most of them use geometric algorithms in...

    Provided By Osaka University

  • White Papers // Dec 2009

    Energy Saving in Intermittent Receiver-Driven Multi-Hop Wireless Sensor Networks

    A major challenge in wireless sensor networks is energy saving. In the Intermittent Receiver-driven Data Transmission (IRDT) protocol, which aims to save energy, communication between nodes commences when multiple receiver nodes transmit their own IDs intermittently and a sender node receives them. The authors' previous research focused on the performance...

    Provided By Osaka University

  • White Papers // May 2010

    Trade-Off Evaluation Between Fairness and Throughput for TCP Congestion Control Mechanisms in a Wireless LAN Environment

    Per-flow unfairness of TCP throughput in the IEEE 802.11 wireless LAN environment has been reported. Although a number of researchers have proposed various methods for alleviating the unfairness, they evaluated the fairness of their methods separately from the network bandwidth utilization, meaning that they did not consider the trade-off relationships...

    Provided By Osaka University

  • White Papers // May 2010

    Dynamics of Feedback-Induced Packet Delay in Power-Law Networks

    Dynamic interactions of various network-related protocols induced by the functional partition make the Internet to be complicated systems; details are hardly captured because of large-scale and heterogeneous structure. One of complex behaviors of the Internet is traffic dynamics. For example, flow control and congestion control performed by end host can...

    Provided By Osaka University

  • White Papers // May 2010

    Robustness of Receiver-Driven Multi-Hop Wireless Network With Soft-State Connectivity Management

    Energy saving and ensuring robust data collection are the big subjects in realization of wireless sensor networks. In the Intermittent Receiver-driven Data Transmission (IRDT) protocol, which aims to save energy and get high reliability, communication between nodes commences when multiple receiver nodes transmit their own IDs intermittently and a sender...

    Provided By Osaka University

  • White Papers // Jun 2010

    Adaptive Virtual Network Topology Control in WDM-Based Optical Networks

    Virtual Network Topology (VNT) is one efficient way to transfer the IP packet over the wavelength-routed optical networks. In recent years various new services have emerged, and IP traffic has been highly fluctuated. Therefore, adaptability against changes of traffic is one of the most important characteristics to accommodate the IP...

    Provided By Osaka University

  • White Papers // Jul 2010

    Estimation of Traffic Amounts on All Links by Using the Information From a Subset of Nodes

    Traffic information is required to perform traffic engineering. However, as the network that require traffic engineering becomes large, the overhead to collect the traffic amount information required for traffic engineering becomes large. In this paper, the authors propose a method to reduce the overhead to collect the traffic amount information....

    Provided By Osaka University

  • White Papers // Oct 2010

    An Inter-Networking Mechanism Using Stepwise Synchronization for Wireless Sensor Networks

    To realize the ambient information society, multiple wireless networks deployed in the region or carried by users are required to cooperate with each other. Since duty cycles and operational frequencies are different among networks, the authors need a mechanism to allow networks to efficiently exchange messages. In this paper, they...

    Provided By Osaka University

  • White Papers // Nov 2010

    Self Transforming to Power Law Topology for Overlay Networks

    Designing the architecture of future network requires the understanding of how a topological structure influences the performance of a network. The paper of the topology known as complex network theory has revealed the omnipresence of power law topology in many real networks. This power law topology is known to provide...

    Provided By Osaka University