• Title/Summary/Keyword: Access and evaluation

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An Evaluation of Access Performance of STEP-based CAD Database (STEP 기반 CAD 데이터베이스의 액세스 성능 평가 실험)

  • Kim, Junh-Wan;Han, Soon-Hung
    • IE interfaces
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    • v.17 no.2
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    • pp.226-232
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    • 2004
  • In shipbuilding area, data sharing is one of the crucial issues. Recently, for collaborative design, ship structural CAD systems adopt the database as its primary storage. Database is useful to deal with the large amount of design information among the heterogeneous design department and design stage. To make the database-based CAD system object-oriented database(OODB) and object-relational database(ORDB) can be used. It is important to select proper database because the CAD system performance mainly depends on access performance of database. In this research, using prototype CAD system from other research, access performance of OODB and ORDB form CAD system was evaluated. STEP application protocol was used as the database schema and experiment was made in query by property and query by region. The results give some idea of how to choose the database for CAD systems.

MODELING AND ANALYSIS FOR OPPORTUNISTIC SPECTRUM ACCESS

  • Lee, Yu-Tae;Sim, Dong-Bo
    • Journal of applied mathematics & informatics
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    • v.29 no.5_6
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    • pp.1295-1302
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    • 2011
  • We present an analytic model of an unslotted opportunistic spectrum access (OSA) network and evaluate its performance such as interruption probability, service completion time, and throughput of secondary users. Numerical examples are given to show the performance of secondary users in cognitive networks. The developed modeling and analysis method can be used to evaluate the performance of various OSA networks.

Prediction Model of Energy Consumption of Wired Access Networks using Machine Learning (기계학습을 이용한 유선 액세스 네트워크의 에너지 소모량 예측 모델)

  • Suh, Yu-Hwa;Kim, Eun-Hoe
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.14 no.1
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    • pp.14-21
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    • 2021
  • Green networking has become a issue to reduce energy wastes and CO2 emission by adding energy managing mechanism to wired data networks. Energy consumption of the overall wired data networks is driven by access networks, expect for end devices. However, on a global scale, it is more difficult to manage centrally energy, measure and model the real energy use and energy savings potential of the access networks. This paper presented the multiple linear regression model to predict energy consumption of wired access networks using supervised learning of machine learning with data collected by existing investigated materials, actual measured values and results of many models. In addition, this work optimized the performance of it by various experiments and predict energy consumption of wired access networks. The performance evaluation of the regression model was achieved by well-knowned evaluation metrics.

Design and Implementation of a Bluetooth LAN access system for VoIP phone (Bluetooth를 이용한 VOIP Phone 의 Wireless LAN Access System 개발)

  • 김정근;김영덕;장태규
    • Proceedings of the IEEK Conference
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    • 2002.06a
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    • pp.343-346
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    • 2002
  • This paper presents a Prototype system developed for a Bluetooth interfaced VoIP system. The VoIP phone is developed based on tile implementation of a CELP coder on the TI 16bit DSP Processor A PC interfaced with Bluetooth module is used to designing a access point system. Host controller protocol stack is implemented to realize gateway between the wireless and wired line networks. A server application program for user management and call processing, which is based on TCP/IP peer to peer connection, is implemented for tile evaluation of overall interface system.

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Development and Performance Evaluation of a Concurrency Control Technique in Object-Oriented Database Systems

  • Jun, Woochun;Hong, Suk-Ki
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.4
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    • pp.1899-1911
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    • 2018
  • In this work, we propose a concurrency control scheme in object-oriented database (OODB). Since an OODB provides complex modeling power than the conventional relational databases, a concurrency control technique in OODB is also rather complicated and has influence on the overall performance. Thus, it is very important to develop a concurrency control technique with less overhead. The proposed scheme deals with class hierarchy that is a key concept in OODBs. The proposed scheme is developed on implicit locking scheme. Also, the proposed scheme is designed using data access frequency in order to reduce locking overhead than implicit locking. It means that, if access frequency information is not available, the proposed scheme works just like the existing implicit locking, In our work, the correctness of the proposed scheme is proved. The performance is analyzed depending on access types. Also, it is proved that our scheme performs works much better than the implicit locking does.

Performance Evaluation of Myopic Policy for Dynamic Spectrum Access (동적 스펙트럼 접속을 위한 myopic 방식의 성능 분석)

  • Lee, Yutae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.5
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    • pp.1101-1105
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    • 2013
  • Due to underutilization of spectrum under the current static spectrum management policy, various kinds of dynamic spectrum access strategies have appeared. Myopic policy is a simple policy with reduced complexity that maximizes the immediate throughput. In this paper, the distribution of its medium access delay is evaluated under saturation traffic conditions. Using the distribution of the medium access delay, we also evaluate its system delay under non-saturated traffic conditions.

Experience in Practical Implementation of Abstraction Interface for Integrated Cloud Resource Management on Multi-Clouds

  • Kim, Huioon;Kim, Hyounggyu;Chun, Kyungwon;Chung, Youngjoo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.1
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    • pp.18-38
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    • 2017
  • Infrastructure-as-a-Service (IaaS) clouds provide infrastructure as a pool of virtual resources, and the public IaaS clouds, e.g. Amazon Web Service (AWS) and private IaaS cloud toolkits, e.g. OpenStack, CloudStack, etc. provide their own application programming interfaces (APIs) for managing the cloud resources they offer. The heterogeneity of the APIs, however, makes it difficult to access and use the multiple cloud services concurrently and collectively. In this paper, we explore previous efforts to solve this problem and present our own implementation of an integrated cloud API, which can make it possible to access and use multiple clouds collectively in a uniform way. The implemented API provides a RESTful access and hides underlying cloud infrastructures from users or applications. We show the implementation details of the integrated API and performance evaluation of it comparing the proprietary APIs based on our cloud testbed. From the evaluation results, we could conclude that the overhead imposed by our interface is negligibly small and can be successfully used for multi-cloud access.

(PMU (Performance Monitoring Unit)-Based Dynamic XIP(eXecute In Place) Technique for Embedded Systems) (내장형 시스템을 위한 PMU (Performance Monitoring Unit) 기반 동적 XIP (eXecute In Place) 기법)

  • Kim, Dohun;Park, Chanik
    • IEMEK Journal of Embedded Systems and Applications
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    • v.3 no.3
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    • pp.158-166
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    • 2008
  • These days, mobile embedded systems adopt flash memory capable of XIP feature since they can reduce memory usage, power consumption, and software load time. XIP provides direct access to ROM and flash memory for processors. However, using XIP incurs unnecessary degradation of applications' performance because direct access to ROM and flash memory shows more delay than that to main memory. In this paper, we propose a memory management framework, dynamic XIP, which can resolve the performance degradation of using XIP. Using a constrained RAM cache, dynamic XIP can dynamically change XIP region according to page access pattern to reduce performance degradation in execution time or energy consumption resulting from native XIP problem. The proposed framework consists of a page profiler gathering applications' memory access pattern using PMU and an XIP manager deciding that a page is accessed whether in main memory or in flash memory. The proposed framework is implemented and evaluated in Linux kernel. Our evaluation shows that our framework can reduce execution time at most 25% and energy consumption at most 22% compared with using XIP-only case adopted in general mobile embedded systems. Moreover, the evaluation shows that in execution time and energy consumption, our modified LRU algorithm with code page filters can reduce more than at most 90% and 80% respectively compared with applying just existing LRU algorithm to dynamic XIP.

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An Evaluation of Library Websites with Universal Design Perspectives (유니버설 디자인 관점에서의 도서관 웹사이트 평가에 관한 연구)

  • Han, Seung-Hee
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.22 no.2
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    • pp.201-220
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    • 2011
  • The library is a social institution that should ensure all users' information access rights. In this study, the concept of universal design is analyzed as a theoretical basis that library Websites should be accessed equitably by all kinds of users, and an evaluation criteria is developed based on the principles of universal design. The Websites of 7 regional central libraries are evaluated with suggested criteria and the ratio of compliance of universal Web design is measured. In the result, the most of the Websites are showed not only high performances on the area of (1) Web accessibility and (2) usability, but low performances on the area of (1) equitable use and (2) flexibility in use.

Efficient Evaluation of Shared Predicates for XForms Page Access Control (XForms 페이지의 접근제어를 위한 공유 조건식의 효율적 계산 방법)

  • Lee, Eun-Jung
    • The KIPS Transactions:PartD
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    • v.15D no.4
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    • pp.441-450
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    • 2008
  • Recently, access control on form-based web information systems has become one of the useful methods for implementing client systems in a service-oriented architecture. In particular, XForms language is being adopted in many systems as a description language for XML-based user interfaces and server interactions. In this paper, we propose an efficient algorithm for the evaluation of XPath-based access rules for XForms pages. In this model, an XForms page is a sequence of queries and the client system performs user interface realization along with XPath rule evaluations. XPath rules have instance-dependent predicates, which for the most part are shared between rules. For the efficient evaluation of shared predicate expressions in access control rules, we proposed a predicate graph model that reuses the previously evaluated results for the same context node. This approach guarantees that each predicate expression is evaluated for the relevant xml node only once.