• The Journal of Information Technology
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• v.5 no.1
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• pp.29-37
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• 2002

Distributed programming can be greatly simplified by language support for distributed communication. Many web browsers now offer some form of distributed objects and the number and types of them are growing daily in interesting and innovative ways CORBA IDL and Java RMI, the representative of distributed object model, support different approaches for distributed computing environments. CORBA approach does not support the application generated by java RMI, even though it supports multiple programming languages. Object translation system between RMI to CORBA is designed and implemented for interoperability of distributed objects on the two different distributed programming environments. Suggested system is considered binding, inheritance, polymorphism, object passing, and callback which are key properties on the distributed objects. Translation System we suggested is implemented on the Window/NT(version 4.0) with Java Development Kit(version 1.1.6).

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.224-226
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• 2005

Grid computing enables the fundamental computing shift from a localized resource computing model to a fully-distributed virtual organization with shared resources. In the grid computing environment, grid users usually get access rights by mapping their credential to local account. The mapped total account is temporally belongs to grid user. So, data on the secondary storage, which is produced by grid operation, can increase the load of system administration or can issue grid user's privacy. In this paper, we design a data management system for grid user to cover these problems. This system implements template account mechanism and manages local grid data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5780-5802
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• 2017

Cloud computing system consists of distributed resources in a dynamic and decentralized environment. Therefore, using cloud computing resources efficiently and getting the maximum profits are still challenging problems to the cloud service providers and cloud service users. It is important to provide the efficient scheduling. To schedule cloud resources, numerous heuristic algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Ant Colony Optimization (ACO), Cuckoo Search (CS) algorithms have been adopted. The paper proposes a Modified Particle Swarm Optimization (MPSO) algorithm to solve the above mentioned issues. We first formulate an optimization problem and propose a Modified PSO optimization technique. The performance of MPSO was evaluated against PSO, and GA. Our experimental results show that the proposed MPSO minimizes the task execution time, and maximizes the resource utilization rate.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.719-724
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• 2007

Many engineering problems often require the large amount of computing resources for iterative simulations of problems treating many parameters and input files. In order to overcome the situation, this paper proposes an e-Science based computational system. The system exploits the Grid computing technology to establish an integrated web service environment which supports distributed high throughput computational simulations and remote executions. The proposed system provides an easy-to-use parametric study service where a computational service includes real time monitoring. To verify usability of the proposed system, two kinds of applications were introduced. The first application is an Aerospace Integrated Research System (e-AIRS). The e-AIRS adapts the proposed computational system to solve CFD problems. The second one is design and optimization of protein 3-dimensional structures.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.3
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• pp.75-85
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• 2012

In general, cellular network is deployed as distributed network architecture, so network equipment is spread out all over the coverage area. This case causes high cost. Recently, centralized network architecture has been deployable at cellular network since base station was able to be virtualized due to advance in computing power. The centralized network architecture in cellular network adjusts its cell radius dynamically and minimizes power consumption of the network. This paper introduces a new centralized deployment way of cellular network using SDR and cloud computing technology. Then, advantage and feasibility of the new network will be reviewed by implementing this novel network.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.217-218
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• 2009

URC 로봇은 고성능 서버를 통해 로봇이 수행할 서비스의 일부를 외부 디바이스에 분담시킴으로써 저렴한 하드웨어로 로봇을 구현하고자 하는 목적을 가지는 지능형 서비스 로봇이다. SOMAR는 유비쿼터스 환경에서 사용자에게 다양한 원격 로봇 서비스를 제공하기 위한 URC 로봇 미들웨어로, URC 로봇 클라이언트와 이를 등록, 제어, 관리하는 서버로 구성된다. SOMAR 서버를 통해 로봇 서비스를 수행하기 위해서는 로봇 클라이언트의 상태정보를 모니터링하여 수행가능 여부를 판단해야 한다. 본 논문은 이러한 상태정보 모니터링을 위해 R-OSGi를 이용한 분산 Observer 패턴을 구현한다. Observer 패턴은 객체간에 느슨한 결합구조를 가져 URC 로봇 클라이언트 모니터링 프로그램의 개발과 수정이 용이하고, 플러그인 방식의 개발을 통해 다양한 프로그램 설치와 응용이 가능하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.651-654
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• 2011

Wi-Fi 는 스마트 네트워크 환경 구현을 위한 기반 분야로 다양한 분야 및 서비스에 활용되고 있다. Wi-Fi 는 AP (Access Point)를 통해 보다 넓은 범위의 네트워크를 가능하게 하며, 여러 무선 단말기와 통신을 한다. 또한 Wi-Fi 는 DCF(Distributed Coordinate Function) 프로토콜을 이용하여 AP 를 포함한 모든 무선 단말기에게 공평하게 채널을 할당한다. 그러나 AP 는 채널을 요청하는 하위 단말기에 대해 도착한 순서에 따라 채널을 할당하는 FIFS(First In First Service) 스케줄링을 사용하여 데이터를 처리함으로써 데이터 전송 신뢰도를 저하시키고, 전송 지연이 발생하여 응급 데이터 전송에 적합하지 않다. 이에 본 논문에서는 응급 데이터 전송을 위한 우선순위 기반 AP 채널 할당 기법을 제안한다. 제안하는 기법은 전송하려는 데이터에 우선순위를 부여하여 응급 데이터의 채널 요청 처리율을 높이고 채널 할당 지연시간을 감소시켜 응급 데이터 전송 신뢰도를 향상시킨다.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.484-493
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• 2001

As real-time database systems are extended to the distributed computing environment, the need to apply the existing real-time concurrency control schemes to the distributed computing environment has been made. In this paper we propose an efficient concurrency control scheme for distributed real-time database system. Our proposed scheme guarantees a transaction to commit at its maximum, reduces the restart of a transaction that is on the prepared commit phase, and minimizes the time of the lock holding. This is because it raises the priority of the transaction that is on the prepared commit phase in the distributed real-time computing environment. In addition, it reduces the waiting time of a transaction that owns borrowed data and improves the performance of the system, as a result of lending the data that the transaction with the raised priority holds. We compare the proposed scheme with DO2PL_PA(Distributed Optimistic Two-Phase Locking) and MIRROR(Managing Isolation in Replicated Real-time Object Repositories) protocol in terms of the arrival rate of transactions, the size of transactions, the write probability of transactions, and the replication degree of data in a firm-deadline real-time database system based on two-phase commit protocol. It is shown through the performance evaluation that our scheme outperforms the existing schemes.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.5
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• pp.583-594
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• 1999

With the advance of VLSI and network technologies, it has now become a common practice to deploy a various forms of distributed computing environments. A study shows that a lot of network-aware computers are in an idle state for considerable amount of time depending on the types of users and time frames of the day. If we can take the full advantage of those idle computers, we can obtain the enormous combined processing power without further costly investment. In this paper, we present a distributed batch-processing system, called the Java Distributed Batch-processing System (JDBS), which allows us to execute CPU-intensive, independent jobs across a pool of idle workstations on top of extant distributed computing environments. Since JDBS is implemented using a Java programming language, it not only extends the scope of machine types that can be joined to the pool, but makes it a lot easier to build an entire system. Besides, JDBS is scalable and fault-tolerant due to its multi-cluster organization and intelligent strategies. A graphical user interface is also provided to facilitate the registration and unregistration, job submission, and job monitoring.

• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.53-62
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• 2005

A challenging task in the LBS system engineering is to implement a highly scalable system architecture which can manage moderate-size configurations handling thousands of moving items as well as upper-end configurations handling distributed computing system architecture that consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone. In this paper, we explain a prototype location data server structuring major components of GALIS by employing the TMO programming scheme, including the execution engine middleware developed to support real-time distributed object programming and real-time distributed computing system design. We present how to generate realistic location sensing reports and how to process such location reports and location-related queries. Some experimental results showing performance factors regarding distributed query processing are also explained.