Ipsj Digital Courier最新文献_第8页

Simulation of Compositional Variation in Liquid Phase Epitaxy InGaP Using a Two Dimensional Model 用二维模型模拟液相外延InGaP的成分变化

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.114

Hiromoto Susawa, T. Tsuji, K. Hiramatsu, T. Jimbo, T. Soga

{"title":"Simulation of Compositional Variation in Liquid Phase Epitaxy InGaP Using a Two Dimensional Model","authors":"Hiromoto Susawa, T. Tsuji, K. Hiramatsu, T. Jimbo, T. Soga","doi":"10.2197/IPSJDC.3.114","DOIUrl":"https://doi.org/10.2197/IPSJDC.3.114","url":null,"abstract":"Compositional variation in initial growth was observed in Liquid Phase Epitaxy (LPE) experiments. It is thought that the cause is the flow of the melt which is induced by the slide of the entire melt from the place where there isn't substrate to the substrate before growth. The phenomenon was simulated with a one dimensional model in InGaP growth with a convection term added to a diffusion-limited model. The velocity of flow in the melt was approximated to Stokes's first problem. It was shown that composition of In in grown solid with the flow is larger than that without the flow. In this paper, InGaP LPE growth is considered and a two dimensional model of the flow is used. For the solute transport, a two dimensional model is also adopted except at the growth interface. A result similar to the one dimensional model was obtained. In the two dimensional model, In composition is greater than that in the case without flow for the greater part of the growth time, but decreases when the flow transports dilute solution. This decrease doesn't appear in the one dimensional model. This phenomenon can be explained by considering the influence of the flow on the mole fraction near the boundary layer.","PeriodicalId":432390,"journal":{"name":"Ipsj Digital Courier","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124799283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluations of Web Server Performance with Heavy-tailedness 重载Web服务器性能评估

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.21

T. Nakashima

{"title":"Evaluations of Web Server Performance with Heavy-tailedness","authors":"T. Nakashima","doi":"10.2197/IPSJDC.3.21","DOIUrl":"https://doi.org/10.2197/IPSJDC.3.21","url":null,"abstract":"Providing quality of service (QoS) in a business environment requires accurate estimation of Internet traffic, especially HTTP traffic. HTTP traffic, mainly consisting of file transmission traffic, depends on the sizes of files with a heavy-tailed property. Analyzing the performance of specific Web servers and comparing server performance is important in QoS provisioning for user applications. In this paper, we present the experimental analysis of Web server performance using our active measurement. We capture activity data from 1984 diverse Web servers by sending measurement packets 20 times in order to evaluate the spatial properties, and we select 14 Web servers to send packets 2, 000 times in 5-second intervals to evaluate the temporal properties. The main contribution of our study is to provide methods of evaluating the temporal and spatial properties on any Web server by measuring from a remote observation host, and to illustrate the current activity of temporal and spatial properties in a series of figures. Crovella's well known work merely describes the self-similar properties for the total transmission time generated by a heavy-tailed file size distribution. We divided the total transmission time into network and server system dependable elements, of which the heavy-tailed properties are captured. We found that temporal properties consist of two factors: stability and activity in the Poisson process. Robustness of heavy-tailedness in terms of constructing elements of total transmission time was evident from the analysis of spatial properties. Finally, we observed the upper boundary and classified groups in a mean-variance plot of primitive elements of the Web server.","PeriodicalId":432390,"journal":{"name":"Ipsj Digital Courier","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121355907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Efficient Channel Utilization Schemes for IEEE 802.11 DCF over MANET 基于MANET的IEEE 802.11 DCF的有效信道利用方案

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.75

Naoki Nakamura, D. Chakraborty, Apichet Chayabejara, G. Kitagata, T. Suganuma, G. Chakraborty, N. Shiratori

引用次数: 0

An Educational Schoolbag System for Providing an Object Reminder Service 提供目标提醒服务的教育书包系统

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.64

Lei Jing, Zixue Cheng, Mizuo Kansen, Tongjun Huang, Shengguo Sun

{"title":"An Educational Schoolbag System for Providing an Object Reminder Service","authors":"Lei Jing, Zixue Cheng, Mizuo Kansen, Tongjun Huang, Shengguo Sun","doi":"10.2197/IPSJDC.3.64","DOIUrl":"https://doi.org/10.2197/IPSJDC.3.64","url":null,"abstract":"Embedding educational functions into devices in the everyday environment is an important task for advocates of ubiquitous learning. In this paper, we discuss how to add a reminder service to a schoolbag. An educational function would be added to the device to help pupils remember belongings. Reminding oneself of things is a difficult task and reminder services have been an important subject of computer applications. However, most reminding tools are used for business, not education. Most such services use PDAs as terminals and require the user to create the reminder list by him or herself, making it too complex for some pupils to use. The systems also seldom pay attention to helping users learn how to avoid forgetting. In this research, a ubiquitous learning support system that makes use of schoolbags is presented to assist pupils in managing their personal items. With RFID and infrared sensors, a microcontroller embedded in a schoolbag can monitor what has been put in or taken out of the schoolbag and automatically maintain a schoolbag's items list. Such a bag also enables teachers to make up a schedule that specifies required items for given days. The microcontroller then compares the schedule with the items list in the schoolbag and provides a reminder service for the pupil. In addition to the reminder service, which is based on principles of behavior modification, the paper also proposes a series of methods to help pupils form good personal management habits and reduce their dependence on outside machines.","PeriodicalId":432390,"journal":{"name":"Ipsj Digital Courier","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114225558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Design and Implementation of Socket-level Bandwidth Aggregation Mechanism for Mobile Networking Environments 移动网络环境下套接字级带宽聚合机制的设计与实现

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.86

H. Sakakibara, M. Saito, H. Tokuda

{"title":"Design and Implementation of Socket-level Bandwidth Aggregation Mechanism for Mobile Networking Environments","authors":"H. Sakakibara, M. Saito, H. Tokuda","doi":"10.2197/IPSJDC.3.86","DOIUrl":"https://doi.org/10.2197/IPSJDC.3.86","url":null,"abstract":"This paper presents a mechanism that aggregates the bandwidths of multiple network interfaces on computers in mobile environments. Research and development on wireless technologies has recently been extremely active. As a result, various kinds of wireless media have been emerging and these have been installed on computers. However, the demand for broader bandwidths has not yet been met. We designed and developed a socket-level bandwidth aggregation mechanism (SBAM) that offer broader bandwidths using multiple wireless interfaces on computers. The most distinctive feature of SBAM is that the mechanism is implemented as a feature of operating systems. This involves two benefits. First, it is possible to deploy SBAM gradually in computers on the Internet. If the bandwidth aggregation mechanism (BAM) is achieved in a network stack, it must be implemented in all computers on the Internet. However, it is not necessary to implement it in all computers on the Internet, since it can recognize its own existence on peer hosts and determine whether to use BAM or not. Second, it does not require modifications to most existing software. For example, if the mechanism is achieved as a feature of a transport protocol, such as TCP, all applications using TCP must be re-written to adapt to the new transport layer protocol. However, SBAM does not require this, since the socket hides the existence of the mechanism. We evaluated SBAM in an actual wireless network environment. We achieved an increase in throughput by a factor of 1.6. SBAM offers broader bandwidths for applications by utilizing various wireless devices on computers while it avoids modifications to existing environments.","PeriodicalId":432390,"journal":{"name":"Ipsj Digital Courier","volume":"28 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120887295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cooperation Strategy for Broadcast Scheduling and Base Station Caching in Hybrid Wireless Broadcast Environment 混合无线广播环境下广播调度与基站缓存的协同策略

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.30

Jing Cai, T. Terada, T. Hara, S. Nishio

引用次数: 2

Congestion Control Using Multilevel Explicit Congestion Notification 使用多级显式拥塞通知的拥塞控制

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.42

A. Durresi, L. Barolli, R. Jain, M. Takizawa

引用次数: 6

Enhancing Multiobjective Evolutionary Algorithms by Local Dominance and Local Recombination: Performance Verification in Multiobjective 0/1 Knapsack Problems 基于局部优势和局部重组的多目标进化算法:多目标0/1背包问题的性能验证

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.98

Hiroyuki Sato, H. Aguirre, Kiyoshi Tanaka

{"title":"Enhancing Multiobjective Evolutionary Algorithms by Local Dominance and Local Recombination: Performance Verification in Multiobjective 0/1 Knapsack Problems","authors":"Hiroyuki Sato, H. Aguirre, Kiyoshi Tanaka","doi":"10.2197/IPSJDC.3.98","DOIUrl":"https://doi.org/10.2197/IPSJDC.3.98","url":null,"abstract":"This paper proposes a method to enhance single population multiobjective evolutionary algorithms (MOEAs) by searching based on local dominance and local recombination. In this method, first, all fitness vectors of individuals are transformed to polar coordinate vectors in objective function space. Then, the population is iteratively divided into several subpopulations by using declination angles. As a result, each sub-population covers a sub-region in the multiobjective space with its individuals located around the same search direction. Next, local dominance is calculated separately for each sub-population after alignment of its principle search direction by rotation. Selection, recombination, and mutation are applied to individuals within each sub-population. The proposed method can improve the performance of MOEAs that use dominance based selection, and can reduce the entire computational cost to calculate dominance among solutions as well. In this paper we verify the effectiveness of the proposed method obtaining Pareto optimal solutions in two representative MOEAs, i.e. NSGA-II and SPEA2, with Multiobjective 0/1 Knapsack Problems.","PeriodicalId":432390,"journal":{"name":"Ipsj Digital Courier","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129660719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

NAL Level Stream Authentication for H.264/AVC 用于H.264/AVC的NAL级流认证

Ipsj Digital Courier Pub Date : 2007-02-15 DOI: 10.2197/IPSJDC.3.55

S. Ueda, H. Shigeno, Ken-ichi Okada

引用次数: 18

Instrogram: Probabilistic Representation of Instrument Existence for Polyphonic Music 复调音乐中乐器存在的概率表示

Ipsj Digital Courier Pub Date : 2007-01-15 DOI: 10.2197/IPSJDC.3.1

Tetsuro Kitahara, Masataka Goto, Kazunori Komatani, T. Ogata, HIroshi G. Okuno

{"title":"Instrogram: Probabilistic Representation of Instrument Existence for Polyphonic Music","authors":"Tetsuro Kitahara, Masataka Goto, Kazunori Komatani, T. Ogata, HIroshi G. Okuno","doi":"10.2197/IPSJDC.3.1","DOIUrl":"https://doi.org/10.2197/IPSJDC.3.1","url":null,"abstract":"This paper presents a new technique for recognizing musical instruments in polyphonic music. Since conventional musical instrument recognition in polyphonic music is performed notewise, i.e., for each note, accurate estimation of the onset time and fundamental frequency (F0) of each note is required. However, these estimations are generally not easy in polyphonic music, and thus estimation errors severely deteriorated the recognition performance. Without these estimations, our technique calculates the temporal trajectory of instrument existence probabilities for every possible F0. The instrument existence probability is defined as the product of a nonspecific instrument existence probability calculated using the PreFEst and a conditional instrument existence probability calculated using hidden Markov models. The instrument existence probability is visualized as a spectrogram-like graphical representation called the instrogram and is applied to MPEG-7 annotation and instrumentation-similaritybased music information retrieval. Experimental results from both synthesized music and real performance recordings have shown that instrograms achieved MPEG-7 annotation (instrument identification) with a precision rate of 87.5% for synthesized music and 69.4% for real performances on average and that the instrumentation similarity measure reflected the actual instrumentation better than an MFCC-based measure.","PeriodicalId":432390,"journal":{"name":"Ipsj Digital Courier","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124032252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 21