Kyoto University

Displaying 1-28 of 28 results

  • White Papers // Sep 2012

    Multi-Flow Scheduling for Coordinated Direct and Relayed Users in Cellular Systems

    There are two basic principles used in wireless network coding to design throughput-efficient schemes: aggregation of communication flows and interference is embraced and subsequently cancelled or mitigated. These principles inspire design of many novel Multi-Flow Transmission (MFT) schemes. Such are the Coordinated Direct/Relay (CDR) schemes, where each basic transmission involves...

    Provided By Kyoto University

  • White Papers // Aug 2012

    Compressed Sensing Based Protocol for Efficient Reconstruction of Sparse Superimposed Data in a Multi-Hop Wireless Sensor Network

    The authors consider a multi-hop wireless sensor network that measures sparse events and propose a simple forwarding protocol based on Compressed Sensing (CS) which does not need any sophisticated Media Access Control (MAC) scheduling, neither a routing protocol, thereby making significant overhead and energy savings. By means of flooding, multiple...

    Provided By Kyoto University

  • White Papers // May 2011

    Credible User Identification using Social Network Analysis in a Q&A Site

    Although recent commercial search engines use the information concerned with Question and Answering (Q&A), it is still difficult to acquire an appropriate content from numerous user-described answers in Q&A sites. In order to identify the credible users to help people find relevant answer, in this paper, the authors propose a...

    Provided By Kyoto University

  • White Papers // Apr 2011

    Gradual Typing for Generics

    Statically and dynamically typed languages have their own benefits. On the one hand, statically typed languages enjoy type safety properties; on the other hand, dynamically typed languages are said to be suitable for rapid prototyping. There is a significant amount of work to integrate both kinds of languages to have...

    Provided By Kyoto University

  • White Papers // Mar 2011

    WindMine: Fast and Effective Mining of Web-Click Sequences

    Given a large stream of users clicking on web sites, how can the people find trends, patterns and anomalies' The authors have developed a novel method, WindMine, and its fine-tuning sibling, WindMine-part, to find patterns and anomalies in such datasets. Their approach has the following advantages: it is effective in...

    Provided By Kyoto University

  • White Papers // Feb 2011

    Improvement of BP-Based CDMA Multiuser Detection by Spatial Coupling

    Kudekar et al. proved that the Belief-Propagation (BP) threshold for low-density parity-check codes can be boosted up to the Maximum-A-Posteriori (MAP) threshold by spatial coupling. In this paper, spatial coupling is applied to randomly spread Code-Division Multiple-Access (CDMA) systems in order to improve the performance of BP-based Multi User Detection...

    Provided By Kyoto University

  • White Papers // Oct 2010

    Wireless Scheduling With Power Control

    The authors are interested in fundamental limits on communication in wireless networks. How much communication throughput is possible? This is an issue of efficient spatial separation, keeping the interference from simultaneously communicating links sufficiently low. The interference scheduling problem is then to schedule an arbitrary set of communication links in...

    Provided By Kyoto University

  • White Papers // Jul 2010

    Iterative Channel Estimation, Detection, and Decoding in Large CDMA Systems

    The large system analysis of randomly spread direct-sequence code-division multiple-access systems operating over frequency-selective fading channels is considered. Iterative Multi-User Detection and Decoding (MUDD) based on generalized posterior mean estimation and single-user sum-product decoding is assumed to be used at the receiver. The Channel State Information (CSI) at the MUDD...

    Provided By Kyoto University

  • White Papers // Apr 2010

    Analysis of Large MIMO DS-CDMA Systems With Imperfect CSI and Spatial Correlation

    The large system analysis of randomly spread MIMO DS-CDMA systems is provided. Correlated Rayleigh fading MIMO channels are assumed for all users. Linear multiuser detection with separate decoding and pilot-aided channel estimation are used. The results imply that with channel estimation, the performance can improve significantly as the correlation between...

    Provided By Kyoto University

  • White Papers // Apr 2010

    A Distance-Aware Forwarding Protocol for Beaconless Communication in Mobile Ad Hoc Networks and Its Performance

    Recently, routing protocols for Mobile Ad hoc NETworks (MANETs) which use position information to improve their efficiency have been actively studied. In this paper, the authors focus on Beacon-Less Routing algorithm (BLR) and propose a new forwarding algorithm that improves BLR and analyze its performance. BLR is efficient to reduce...

    Provided By Kyoto University

  • White Papers // Jan 2010

    Estimating The Distribution Of Inflation Expectations

    In this paper, the authors use survey data to estimate the shape of the distribution of inflation expectations. However, unlike previous studies, they do not assume a distribution a priori. They employ an applied approximation method using normal distribution: Cornish-Fisher expansion. Skewness and kurtosis may provide necessary information for understanding...

    Provided By Kyoto University

  • White Papers // Dec 2009

    Considering Fixed-Mobile Convergence Service as a Two-Sided Market

    This paper considers the rapidly developing Fixed-Mobile Convergence (FMC) service as a two-sided market and analyzes the price structure a la Bertrand-Nash based on revealed preference data. The price structure is calculated such that the price-cost margin is higher for NTT's relatively advantageous fixed-line Internet service and lower for NTT's...

    Provided By Kyoto University

  • White Papers // Nov 2009

    Indeterminacy And Business-Cycle Fluctuations In A Two-Sector Economy With Externalities

    The authors consider a two-sector economy with money-in-the-utility-function and sector-specific externalities. They provide conditions on technologies leading to the existence of local indeterminacy for any value of the interest rate elasticity of money demand, pro-vided the elasticity of intertemporal substitution in consumption is large enough. Moreover, they show that the...

    Provided By Kyoto University

  • White Papers // Oct 2009

    Modeling User Cooperation Problem in Mobile Overlay Multicast as a Multi-Agent System

    The growth in broadband access and increases in terminal capability have enabled the authors to provide large-scale multimedia services. The traditional unicast architecture cannot support such a service because the transportation from a content server to many end hosts causes the overload to a content server. Overlay multicast techniques have...

    Provided By Kyoto University

  • White Papers // Oct 2009

    A Virtual Layered Space-Frequency Communication Architecture with Iterative Decoding

    In this paper, the authors develop virtual layered space-frequency communication architecture. This architecture enables the decoding of transmitted OFDM (Orthogonal Frequency Division Multiplexing)-QPSK signals even if the number of antennas at the transmitter is twice the number of antennas at the receiver over multipath fading channels. Furthermore, they propose two...

    Provided By Kyoto University

  • White Papers // Oct 2009

    Seeing Past Rivals: Visualizing Evolution of Coordinate Terms Over Time

    In this paper, the authors describe an approach for detection and visualization of coordinate term relationships over time and their evolution using temporal data available on the Web. Coordinate terms are terms with the same hypernym and they often represent rival or peer relationships of underlying objects. The authors have...

    Provided By Kyoto University

  • White Papers // Aug 2009

    Analysis of Information Security Problem by Probabilistic Risk Assessment

    The information security risk assessment is investigated from perspectives of most advanced Probabilistic Risk Assessment (PRA) for nuclear power plants. Accident scenario enumeration by initiating events, mitigation systems and event trees are first described and demonstrated. Assets, confidentiality, integrity, availability, threats, vulnerabilities, impacts, likelihoods, and safeguards are reformulated by the...

    Provided By Kyoto University

  • White Papers // Aug 2009

    How Much Training Is Needed for Iterative Multiuser Detection and Decoding?

    This paper studies large randomly spread direct-sequence code-division multiple-access system operating over a block fading multipath channel. Channel knowledge is obtained by a linear estimator whose initial decisions are iteratively refined by using a soft feedback from the single-user decoders. In addition to the traditional training symbol based signaling scheme,...

    Provided By Kyoto University

  • White Papers // Apr 2009

    On Asymptotic Performance of Iterative Channel and Data Estimation in Large DS-CDMA Systems

    The authors study the spectral efficiency of large random direct-sequence code-division multiple-access systems utilizing Linear Minimum Mean Square Error (LMMSE) channel estimation and iterative Multi-User Detection and Decoding (MUDD). The iterative MUDD based on non-linear data estimation and single-user decoding is considered as a benchmark for the more practical iterative...

    Provided By Kyoto University

  • White Papers // Apr 2009

    Iterative Channel and Data Estimation: Framework and Analysis Via Replica Method

    The large system analysis of a randomly spread direct-sequence code-division multiple-access system operating over a frequency-selective fading channel is considered. Iterative multiuser detection and decoding based on generalized posterior mean estimation and interference cancellation is assumed. The channel is mismatched and provided by a linear estimator whose initial pilot-based decisions...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Economic Growth, Unemployment, And Business Cycles

    This paper explores relationships among economic growth, unemployment, and business cycles by constructing a model, which views the process of creative destruction as a major source of business cycles, as well as of economic growth. The main results are as follows: first, the long-run growth rate has a negative relationship...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Entry, Exit, And Endogenous Growth

    This paper presents an endogenous growth model, in which entry, exit, and growth are endogenously determined through the rational behavior of agents, to investigate the effects of growth-enhancing policies on the exit rate of firms, and on the unemployment rate as well. Unlike standard Schumpeterian growth models, the exit of...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Effects Of Exit On Growth In An Imperfectly Competitive Economy

    This paper develops a tractable model for the simultaneous investigation of the exit of firms and economic growth. Using this model, it shows that the existence of exit of firms weakens the positive effects of an intensified product market competition on the growth rate. A more intense product market competition...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Viewpoint of ISO GMITS and Probabilistic Risk Assessment in Information Security

    Viewing the previous studies on the quantification of information security risks, one of the most popular tools is ISO GMITS, which quantifies the risk of information asset on the whole based on the scores of information asset, threat, and vulnerability. However, in her previous study, the author maintained that "Probabilistic...

    Provided By Kyoto University

  • White Papers // Mar 2009

    A Dynamic Game Model Of Endogenous Growth With Consumption Externalities

    This paper introduces consumption externalities into an endogenous growth model of general capital accumulation and characterizes balanced growth equilibria. Contrary to the common argument in previous studies, the authors show that the growth rate in a feedback Nash equilibrium can be higher than that in an open-loop Nash equilibrium if...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Education, Innovation, And Long-Run Growth

    This paper combines three prototype endogenous growth models, the models with human capital accumulation introduced by Uzawa [1965] and Lucas [1988], variety expansion by Romer [1990], and quality improvements by Aghion and Howitt [1992], in order to investigate how these three engines of growth interact. The authors show that a...

    Provided By Kyoto University

  • White Papers // Sep 2008

    Asymptotic Analysis of Iterative Channel Estimation and Multiuser Detection With Soft Feedback in Multipath Channels

    The large system performance analysis of a randomly spread direct-sequence code-division multiple-access system operating over a frequency-selective channel is considered. The receiver uses iterative channel estimation and Multi-User Detection (MUD), recently analyzed for hard decision feedback by Li et al. (2007). The authors consider the case where soft information is...

    Provided By Kyoto University

  • White Papers // Oct 2007

    Outline of OROCHI: A Multiple Instruction Set Executable SMT Processor

    In recent years, enjoying multimedia contents with portable devices become popular. These multimedia processing workloads are too heavy workload for a conventional processor so that current portable devices implement additional dedicated processor for multimedia processing. But, the authors have to left conventional processor to execute OS and miscellaneous processing so...

    Provided By Kyoto University

  • White Papers // Jul 2010

    Iterative Channel Estimation, Detection, and Decoding in Large CDMA Systems

    The large system analysis of randomly spread direct-sequence code-division multiple-access systems operating over frequency-selective fading channels is considered. Iterative Multi-User Detection and Decoding (MUDD) based on generalized posterior mean estimation and single-user sum-product decoding is assumed to be used at the receiver. The Channel State Information (CSI) at the MUDD...

    Provided By Kyoto University

  • White Papers // Mar 2009

    A Dynamic Game Model Of Endogenous Growth With Consumption Externalities

    This paper introduces consumption externalities into an endogenous growth model of general capital accumulation and characterizes balanced growth equilibria. Contrary to the common argument in previous studies, the authors show that the growth rate in a feedback Nash equilibrium can be higher than that in an open-loop Nash equilibrium if...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Economic Growth, Unemployment, And Business Cycles

    This paper explores relationships among economic growth, unemployment, and business cycles by constructing a model, which views the process of creative destruction as a major source of business cycles, as well as of economic growth. The main results are as follows: first, the long-run growth rate has a negative relationship...

    Provided By Kyoto University

  • White Papers // Apr 2011

    Gradual Typing for Generics

    Statically and dynamically typed languages have their own benefits. On the one hand, statically typed languages enjoy type safety properties; on the other hand, dynamically typed languages are said to be suitable for rapid prototyping. There is a significant amount of work to integrate both kinds of languages to have...

    Provided By Kyoto University

  • White Papers // Mar 2011

    WindMine: Fast and Effective Mining of Web-Click Sequences

    Given a large stream of users clicking on web sites, how can the people find trends, patterns and anomalies' The authors have developed a novel method, WindMine, and its fine-tuning sibling, WindMine-part, to find patterns and anomalies in such datasets. Their approach has the following advantages: it is effective in...

    Provided By Kyoto University

  • White Papers // Aug 2012

    Compressed Sensing Based Protocol for Efficient Reconstruction of Sparse Superimposed Data in a Multi-Hop Wireless Sensor Network

    The authors consider a multi-hop wireless sensor network that measures sparse events and propose a simple forwarding protocol based on Compressed Sensing (CS) which does not need any sophisticated Media Access Control (MAC) scheduling, neither a routing protocol, thereby making significant overhead and energy savings. By means of flooding, multiple...

    Provided By Kyoto University

  • White Papers // Apr 2010

    A Distance-Aware Forwarding Protocol for Beaconless Communication in Mobile Ad Hoc Networks and Its Performance

    Recently, routing protocols for Mobile Ad hoc NETworks (MANETs) which use position information to improve their efficiency have been actively studied. In this paper, the authors focus on Beacon-Less Routing algorithm (BLR) and propose a new forwarding algorithm that improves BLR and analyze its performance. BLR is efficient to reduce...

    Provided By Kyoto University

  • White Papers // Sep 2012

    Multi-Flow Scheduling for Coordinated Direct and Relayed Users in Cellular Systems

    There are two basic principles used in wireless network coding to design throughput-efficient schemes: aggregation of communication flows and interference is embraced and subsequently cancelled or mitigated. These principles inspire design of many novel Multi-Flow Transmission (MFT) schemes. Such are the Coordinated Direct/Relay (CDR) schemes, where each basic transmission involves...

    Provided By Kyoto University

  • White Papers // Apr 2010

    Analysis of Large MIMO DS-CDMA Systems With Imperfect CSI and Spatial Correlation

    The large system analysis of randomly spread MIMO DS-CDMA systems is provided. Correlated Rayleigh fading MIMO channels are assumed for all users. Linear multiuser detection with separate decoding and pilot-aided channel estimation are used. The results imply that with channel estimation, the performance can improve significantly as the correlation between...

    Provided By Kyoto University

  • White Papers // Aug 2009

    How Much Training Is Needed for Iterative Multiuser Detection and Decoding?

    This paper studies large randomly spread direct-sequence code-division multiple-access system operating over a block fading multipath channel. Channel knowledge is obtained by a linear estimator whose initial decisions are iteratively refined by using a soft feedback from the single-user decoders. In addition to the traditional training symbol based signaling scheme,...

    Provided By Kyoto University

  • White Papers // Apr 2009

    On Asymptotic Performance of Iterative Channel and Data Estimation in Large DS-CDMA Systems

    The authors study the spectral efficiency of large random direct-sequence code-division multiple-access systems utilizing Linear Minimum Mean Square Error (LMMSE) channel estimation and iterative Multi-User Detection and Decoding (MUDD). The iterative MUDD based on non-linear data estimation and single-user decoding is considered as a benchmark for the more practical iterative...

    Provided By Kyoto University

  • White Papers // Apr 2009

    Iterative Channel and Data Estimation: Framework and Analysis Via Replica Method

    The large system analysis of a randomly spread direct-sequence code-division multiple-access system operating over a frequency-selective fading channel is considered. Iterative multiuser detection and decoding based on generalized posterior mean estimation and interference cancellation is assumed. The channel is mismatched and provided by a linear estimator whose initial pilot-based decisions...

    Provided By Kyoto University

  • White Papers // Sep 2008

    Asymptotic Analysis of Iterative Channel Estimation and Multiuser Detection With Soft Feedback in Multipath Channels

    The large system performance analysis of a randomly spread direct-sequence code-division multiple-access system operating over a frequency-selective channel is considered. The receiver uses iterative channel estimation and Multi-User Detection (MUD), recently analyzed for hard decision feedback by Li et al. (2007). The authors consider the case where soft information is...

    Provided By Kyoto University

  • White Papers // Aug 2009

    Analysis of Information Security Problem by Probabilistic Risk Assessment

    The information security risk assessment is investigated from perspectives of most advanced Probabilistic Risk Assessment (PRA) for nuclear power plants. Accident scenario enumeration by initiating events, mitigation systems and event trees are first described and demonstrated. Assets, confidentiality, integrity, availability, threats, vulnerabilities, impacts, likelihoods, and safeguards are reformulated by the...

    Provided By Kyoto University

  • White Papers // Oct 2009

    Modeling User Cooperation Problem in Mobile Overlay Multicast as a Multi-Agent System

    The growth in broadband access and increases in terminal capability have enabled the authors to provide large-scale multimedia services. The traditional unicast architecture cannot support such a service because the transportation from a content server to many end hosts causes the overload to a content server. Overlay multicast techniques have...

    Provided By Kyoto University

  • White Papers // Oct 2009

    A Virtual Layered Space-Frequency Communication Architecture with Iterative Decoding

    In this paper, the authors develop virtual layered space-frequency communication architecture. This architecture enables the decoding of transmitted OFDM (Orthogonal Frequency Division Multiplexing)-QPSK signals even if the number of antennas at the transmitter is twice the number of antennas at the receiver over multipath fading channels. Furthermore, they propose two...

    Provided By Kyoto University

  • White Papers // May 2011

    Credible User Identification using Social Network Analysis in a Q&A Site

    Although recent commercial search engines use the information concerned with Question and Answering (Q&A), it is still difficult to acquire an appropriate content from numerous user-described answers in Q&A sites. In order to identify the credible users to help people find relevant answer, in this paper, the authors propose a...

    Provided By Kyoto University

  • White Papers // Oct 2007

    Outline of OROCHI: A Multiple Instruction Set Executable SMT Processor

    In recent years, enjoying multimedia contents with portable devices become popular. These multimedia processing workloads are too heavy workload for a conventional processor so that current portable devices implement additional dedicated processor for multimedia processing. But, the authors have to left conventional processor to execute OS and miscellaneous processing so...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Viewpoint of ISO GMITS and Probabilistic Risk Assessment in Information Security

    Viewing the previous studies on the quantification of information security risks, one of the most popular tools is ISO GMITS, which quantifies the risk of information asset on the whole based on the scores of information asset, threat, and vulnerability. However, in her previous study, the author maintained that "Probabilistic...

    Provided By Kyoto University

  • White Papers // Dec 2009

    Considering Fixed-Mobile Convergence Service as a Two-Sided Market

    This paper considers the rapidly developing Fixed-Mobile Convergence (FMC) service as a two-sided market and analyzes the price structure a la Bertrand-Nash based on revealed preference data. The price structure is calculated such that the price-cost margin is higher for NTT's relatively advantageous fixed-line Internet service and lower for NTT's...

    Provided By Kyoto University

  • White Papers // Oct 2009

    Seeing Past Rivals: Visualizing Evolution of Coordinate Terms Over Time

    In this paper, the authors describe an approach for detection and visualization of coordinate term relationships over time and their evolution using temporal data available on the Web. Coordinate terms are terms with the same hypernym and they often represent rival or peer relationships of underlying objects. The authors have...

    Provided By Kyoto University

  • White Papers // Nov 2009

    Indeterminacy And Business-Cycle Fluctuations In A Two-Sector Economy With Externalities

    The authors consider a two-sector economy with money-in-the-utility-function and sector-specific externalities. They provide conditions on technologies leading to the existence of local indeterminacy for any value of the interest rate elasticity of money demand, pro-vided the elasticity of intertemporal substitution in consumption is large enough. Moreover, they show that the...

    Provided By Kyoto University

  • White Papers // Feb 2011

    Improvement of BP-Based CDMA Multiuser Detection by Spatial Coupling

    Kudekar et al. proved that the Belief-Propagation (BP) threshold for low-density parity-check codes can be boosted up to the Maximum-A-Posteriori (MAP) threshold by spatial coupling. In this paper, spatial coupling is applied to randomly spread Code-Division Multiple-Access (CDMA) systems in order to improve the performance of BP-based Multi User Detection...

    Provided By Kyoto University

  • White Papers // Oct 2010

    Wireless Scheduling With Power Control

    The authors are interested in fundamental limits on communication in wireless networks. How much communication throughput is possible? This is an issue of efficient spatial separation, keeping the interference from simultaneously communicating links sufficiently low. The interference scheduling problem is then to schedule an arbitrary set of communication links in...

    Provided By Kyoto University

  • White Papers // Jan 2010

    Estimating The Distribution Of Inflation Expectations

    In this paper, the authors use survey data to estimate the shape of the distribution of inflation expectations. However, unlike previous studies, they do not assume a distribution a priori. They employ an applied approximation method using normal distribution: Cornish-Fisher expansion. Skewness and kurtosis may provide necessary information for understanding...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Entry, Exit, And Endogenous Growth

    This paper presents an endogenous growth model, in which entry, exit, and growth are endogenously determined through the rational behavior of agents, to investigate the effects of growth-enhancing policies on the exit rate of firms, and on the unemployment rate as well. Unlike standard Schumpeterian growth models, the exit of...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Effects Of Exit On Growth In An Imperfectly Competitive Economy

    This paper develops a tractable model for the simultaneous investigation of the exit of firms and economic growth. Using this model, it shows that the existence of exit of firms weakens the positive effects of an intensified product market competition on the growth rate. A more intense product market competition...

    Provided By Kyoto University

  • White Papers // Mar 2009

    Education, Innovation, And Long-Run Growth

    This paper combines three prototype endogenous growth models, the models with human capital accumulation introduced by Uzawa [1965] and Lucas [1988], variety expansion by Romer [1990], and quality improvements by Aghion and Howitt [1992], in order to investigate how these three engines of growth interact. The authors show that a...

    Provided By Kyoto University