• Title/Summary/Keyword: Distributed Virtual Environment

Search Result 172, Processing Time 0.035 seconds

Garbage Collection Synchronization Technique for Improving Tail Latency of Cloud Databases (클라우드 데이터베이스에서의 꼬리응답시간 감소를 위한 가비지 컬렉션 동기화 기법)

  • Han, Seungwook;Hahn, Sangwook Shane;Kim, Jihong
    • Journal of KIISE
    • /
    • v.44 no.8
    • /
    • pp.767-773
    • /
    • 2017
  • In a distributed system environment, such as a cloud database, the tail latency needs to be kept short to ensure uniform quality of service. In this paper, through experiments on a Cassandra database, we show that long tail latency is caused by a lack of memory space because the database cannot receive any request until free space is reclaimed by writing the buffered data to the storage device. We observed that, since the performance of the storage device determines the amount of time required for writing the buffered data, the performance degradation of Solid State Drive (SSD) due to garbage collection results in a longer tail latency. We propose a garbage collection synchronization technique, called SyncGC, that simultaneously performs garbage collection in the java virtual machine and in the garbage collection in SSD concurrently, thus hiding garbage collection overheads in the SSD. Our evaluations on real SSDs show that SyncGC reduces the tail latency of $99.9^{th}$ and, $99.9^{th}-percentile$ by 31% and 36%, respectively.

Distribution and Abundance of Japanese Anchovy Engraulis japonicus and Other Fishes in Asan Bay, Korea, estimated Hydroacoustic Survey (수산음향기법을 이용한 아산만 멸치(Engraulis japonicus)와 기타어군의 분포 및 현존량 추정)

  • Lee, Hyung-Been;Kang, Don-Hyug;Im, Yang-Jae;Lee, Kyoung-Hoon
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.47 no.5
    • /
    • pp.671-681
    • /
    • 2014
  • The distribution and abundance of coastal fish species in Asan Bay, Korea, were estimated from hydroacoustic survey and net catches. Acoustic data were collected with 38 and 200 kHz from July to October of 2012, and converted to the nautical area scattering coefficient (NASC, $m^2/mile^2$) for $0.25n{\cdot}mile$ along ten transects. Japanese anchovy Engraulis japonicus was the dominant specie in the net catches. The virtual echogram technique was used to distinguish E. japonicus from other species based on the differences in the mean volume backscattering strength (${\Delta}MVBS$) at 38 and 200 kHz. Engraulis japonicus and other fishes are mainly distributed in the center channel and outer part of Asan Bay. E. japonicus tends to move from inner to outer Asan Bay in summer and fall. From NASC data, the target strength and length-weight function of E. japonicus and other fishes were used to estimate the E. japonicus stock at 24.1-93.3 tons, and other fish at 40.6-88.4 tons from July to October 2012. The estimated anchovy biomass compared well with the cumulative catch weight from stow net catches. The hydroacoustic method offers an approach to understanding spatial/temporal structure and estimating the biomass of fish aggregations in coastal areas.

Resource Management Scheme in Proxy-Based Mobile Grid (프록시기반 모바일 그리드에서 자원관리 기법)

  • Cho, InSeock;Lee, DaeWon;Lee, HwaMin;Gil, JoonMin;Yu, HeonChang
    • The Journal of Korean Association of Computer Education
    • /
    • v.11 no.5
    • /
    • pp.67-76
    • /
    • 2008
  • Grid computing has a large scale virtual computing environment that enables a collaborative processing through sharing resources of geographically distributed organizations. In recent year, the development of wireless networks and mobile devices enables mobile devices to consider as a resource of the grids. However, there are some problems such as low performance of processors, small capacity of storages, limited capacity of battery, and low bandwidth. In this paper, to overcome these limitations occurred in mobile grid environments, we proposed a proxy-based mobile grid system. Our proposed system enables mobile devices to play roles as a resource consumer and a resource provider and to collaborate with wired grids through a mobile router. Also, we propose an adaptive job scheduling scheme to cope with context changes of mobile devices and compare our scheduling scheme with other scheduling schemes using a simulation tool, SimGrid, to verify the validity of our job scheduling scheme.

  • PDF

Concept Design of Download Over-the-Air functions for IoF-Cloud based distributed IoT device (IoF-Cloud 기반 분산된 IoT 장비들을 위한 Download Over-the-Air 기능의 개념 설계)

  • Cha, ByungRae;Choi, MyeongSoo;Park, Sun;Kim, HyeongGyun;Kim, YongIl;Kim, JongWon
    • Smart Media Journal
    • /
    • v.5 no.4
    • /
    • pp.9-17
    • /
    • 2016
  • Over the next 20 years it will begin the exodus from the Internet and smart phones to the Internet of Things. The heart of IoT gives new utility and value with connectivity among things around people to the human. In future, Industrial environment will be intimately connect all among machines and machines or factories and factories in all processing, and by digitizing of all goods and production life-cycle, which is a combination of virtual world and real world, the digital factory will become reality eventually. The proposed IoT or IIoT based Download OTA (Over-the-Air) provides a flexible mechanism for downloading Media objects of any type and size from a network. Moreover, proposed IoT based DLOTA provides a part of security by lightweight encryption, OTP, and CapBAC technique.

A Study on Human-Robot Interface based on Imitative Learning using Computational Model of Mirror Neuron System (Mirror Neuron System 계산 모델을 이용한 모방학습 기반 인간-로봇 인터페이스에 관한 연구)

  • Ko, Kwang-Enu;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
    • /
    • v.23 no.6
    • /
    • pp.565-570
    • /
    • 2013
  • The mirror neuron regions which are distributed in cortical area handled a functionality of intention recognition on the basis of imitative learning of an observed action which is acquired from visual-information of a goal-directed action. In this paper an automated intention recognition system is proposed by applying computational model of mirror neuron system to the human-robot interaction system. The computational model of mirror neuron system is designed by using dynamic neural networks which have model input which includes sequential feature vector set from the behaviors from the target object and actor and produce results as a form of motor data which can be used to perform the corresponding intentional action through the imitative learning and estimation procedures of the proposed computational model. The intention recognition framework is designed by a system which has a model input from KINECT sensor and has a model output by calculating the corresponding motor data within a virtual robot simulation environment on the basis of intention-related scenario with the limited experimental space and specified target object.

Multi-group Information Management Techniques to efficiently Protect User Privacy in Heterogeneous Environments of 5G (5G의 이질적인 환경에서 사용자 프라이버시를 효율적으로 보호하기 위한 다중 그룹 정보 관리 기법)

  • Kim, Kyoum-Sun;Yon, Yong-Ho;Jeong, Yoon-Su
    • Journal of Convergence for Information Technology
    • /
    • v.9 no.7
    • /
    • pp.1-7
    • /
    • 2019
  • With the recent commercialization of the next generation of wireless 5G in everyday life, many changes have been made to organizations, industries and businesses of various sizes in various fields. However, although the improved speed and latency of 5G has improved, improvements in encryption, authentication and privacy are still required. In this paper, multiple groups of information management techniques are proposed to efficiently protect users' privacy in the heterogeneous environment of 5G. The proposed technique aims to allow distributed management of users' privacy links by clouding the privacy information generated by different heterogeneous devices to efficiently interface with different groups. Suggestion techniques process user-specific privacy information independently in a virtual space so that users can periodically synchronize their privacy information.

Location Tracking and Remote Monitoring system of Home residents using ON/OFF Switches and Sensors (ON/OFF 스위치와 센서를 이용한 홈 거주자의 위치추적 및 원격모니터링 시스템)

  • Ahn Dong-In;Kim Myung-Hee;Joo Su-Chong
    • Journal of KIISE:Computing Practices and Letters
    • /
    • v.12 no.1
    • /
    • pp.66-77
    • /
    • 2006
  • In this paper, we researched the searching and tracking locations of a home resident using ON/OFF switches and sensors and designed a remote monitoring system. As an implementation environment, this system is developed on the base of the distributed object group framework we have developed from previous works. In order to trace the moving locations of a home resident, we firstly showed a home structure which attaches ON/OFF switches and sensors to home appliances and indoor facilities being fixed in home. Whenever a home resident opens/closes these objects, the signals operated from ON/OFF switches and sensors are sent to a home server system. In this time, the real locations of ON/OFF switches and sensors that the signals are being occurred must be the current location that he/she stays. A home server system provides the functionalities that map the real location of a resident in home to virtual location designed on remote desk-tops or terminals like PDAs, and that construct a healthcare database consisted of moving patterns, moving ranges, momentum for analyzing the given searching locations and times Finally, this system provides these information for remotely monitoring services.

Design and Implementation of an Industrial-Design Collaborative System to Support Scalability (확장성을 고려한 산업디자인 협력시스템 설계 및 구현)

  • Yang, Jin-Mo;Lee, Seung-Ryong;Jeon, Tae-Woong
    • Journal of KIISE:Computing Practices and Letters
    • /
    • v.6 no.5
    • /
    • pp.513-527
    • /
    • 2000
  • This paper describes our experience to design and implementation of a collaborative system framework that allows to develop certain collaborative applications such as 3D animation, computer game, and industrial design. The collaborative system enables users, who located in geographically long distance, to do collaborative work in a single virtual space. The proposed system basically consists of client and server system. The goal of proposed system is to support scalability, portability, and platform independent. In order to achieve these, the server is implemented in Java platform and is adopted to the hybrid architecture which takes the advantages both in centralized and decentralized collaborative system. We construct the server base on its functional characteristics so called User Manager Server (UMS), Session Manager Server (SMS), and Information Server (IS), The UMS manages the users who are taking part in the collaborative operations. The SMS supports the conferencing in the proposed system. The IS provides the connection methods among the UMSs. For user's convenience, we implement the client using Visual C++ in Windows. We also expend the functions of 3D Studio Max to distributed environment by means of the plug-in module, and facilitate the chatting and white board functions as well.

  • PDF

A Robustness Test Method and Test Framework for the Services Composition in the Service Oriented Architecture (SOA에서 서비스 조합의 강건성 테스트 방법 및 테스트 프레임워크)

  • Kuk, Seung-Hak;Kim, Hyeon-Soo
    • Journal of KIISE:Software and Applications
    • /
    • v.36 no.10
    • /
    • pp.800-815
    • /
    • 2009
  • Recently, Web services based service-oriented architecture is widely used to integrate effectively various applications distributed on the networks. In the service-oriented architecture BPEL as a standard modeling language for the business processes provides the way to integrate various services provided by applications. Over the past few years, some types of studies have been made on testing compatibility of services and on discriminating and tracing of the business processes in the services composition. Now a lot of studies about the services composition with BPEL are going on. However there were few efforts to solve the problems caused by the services composition. Especially, there is no effort to evaluate whether a composite service is reliable and whether it is robust against to exceptional situations. In this paper, we suggest a test framework and a testing method for robustness of the composite service written in WS-BPEL. For this, firstly we extract some information from the BPEL process and the participant services. Next, with the extracted information we construct the virtual testing environment that generates various faults and exceptional cases which may be raised within the real services. Finally the testing work for robustness of a composite service is performed on the test framework.

Debelppment of C++ Compiler and Programming Environment (C++컴파일러 및 프로그래밍 환경 개발)

  • Jang, Cheon-Hyeon;O, Se-Man
    • The Transactions of the Korea Information Processing Society
    • /
    • v.4 no.3
    • /
    • pp.831-845
    • /
    • 1997
  • In this paper,we proposed and developed a compiler and interactive programming enviroments for C++ wich is mostly worth of nitice among the object -oriented languages.To develope the compiler for C++ we took front=end/back-end model using EM virtual machine.In develpoing Front-End,we formailized C++ gram-mar with the context semsitive tokens which must be manipulated by dexical scanner and designed a AST class li-brary which is the hierarchy of AST node class and well defined interface among them,In develpoing Bacik-End,we proposed model for three major components :code oprtimizer,code generator and run-time enviroments.We emphasized the retargatable back-end which can be systrmatically reconfigured to genrate code for a variety of distinct target computers.We also developed terr pattern matching algorithm and implemented target code gen-erator which produce SPARC code.We also proposed the theroy and model for construction interative pro-gramming enviroments. To represent language features we adopt AST as internal reprsentation and propose uncremental analysis algorithm and viseal digrams.We also studied unparsing scheme, visual diagram,graphical user interface to generate interactive environments automatically Results of our resarch will be very useful for developing a complier and programming environments, and also can be used in compilers for parallel and distributed enviroments.

  • PDF