• Journal of KIISE:Software and Applications
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• v.26 no.9
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• pp.1061-1072
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• 1999

한 개 이상의 사이트에 공간 데이타가 중복 저장된 분산 공간 DB에서, 동시에 수행될 수 있는 긴 트랜잭션의 변경은 일관성 제어를 위해 다른 사이트에 전파되어야 한다. 이때 같은 영역의 공간 데이타를 서로 다른 사이트에서 동시에 변경할 경우, 변경 상충 문제가 발생하거나 잠금 기법에 의한 오랜 대기 시간이 초래되는 문제가 있다. 또한 공간 객체는 잠금의 대상이 아닌 공간 관련성에 의한 종속성을 가진다.이 논문은 긴 트랜잭션으로 중복된 공간 데이타를 변경할 경우 중복 제어를 위한 변경 전파와 동시성 제어 문제를 다룬다. 중복된 공간 데이타의 변경 병렬성을 향상시키기 위해 영역 잠금 및 SR-bound WRITE 잠금 기법을 제시한다. 한 사이트에서 수정하는 객체들과 다른 사이트에서 수정하는 객체들 사이에 공간 관련성에 의한 종속성이 없을 경우 병렬 수정을 허용하도록 제어하며, 공간 관련성에 의한 종속성이 있을 경우 SR-based 2PC라 불리는, 확장된 2단계 완료 프로토콜로 협동작업을 수행해서 변경 상충을 해결하는 새로운 중복 제어 기법을 설계하고 구현한다.Abstract The update of a long transaction should be propagated to the other sites for consistency control, when spatial database are replicated at multiple sites to achieve availability, reliability, and performance. When the replicated spatial data are updated at the same time, the update of one site would be conflicted with the other or a user would not be able to access the replicated spatial data under the control of locking. Two spatial objects having spatial relationships should be cooperatively updated even if there are no conflicts of locking for them.This paper deals with the issues of concurrency control and update propagation of replicated spatial data. We present the concept of region lock and SR-bound WRITE lock for enhancing the parallelism of updating the replicated spatial data. If there are no spatial relationships between one site's objets and the other's objects, parallel update would be allowed. Concurrent update of two spatial objects having spatial relationships should be propagated and cooperated by using an extended two-phase commit protocol, called spatial relationship-based 2PC.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.2
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• pp.183-194
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• 2002

The clustering environment with heterogeneous workstations provides the cost effectiveness and usability for executing applications in parallel. Load balancing is considered a necessary feature for a cluster of heterogeneous workstations to minimize the turnaround time. Previously, static load balancing that assigns a predetermined weight for the processing capability of each workstation, or dynamic approaches which execute a benchmark program to get relative processing capability of each workstation were proposed. The execution of the benchmark program, which has nothing to do with the application being executed, consumes the computation time and the overall turnaround time is delayed. In this paper, we present efficient methods for task distribution and task migration, based on the relative load index. We designed and implemented a load balancing system for the clustering environment with heterogeneous workstations. Turnaround times of our methods and the round-robin approach, as well as the load balancing method using a benchmark program, were compared. The experimental results show that our methods outperform all the other methods that we compared.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.669-676
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• 2016

North Korea has various ballistic missiles from short range to long range such as inter continental ballistic missiles. Short range ballistic missiles such as SCUD series are threatening to Korea peninsula. Therefore Korea is constructing various missile defense systems to protect country. Parameters influencing the received power from the target to the radar are transmitting power, antenna gain, carrier frequency, RCS(Radar Cross Section) of target and distance from radar to target. Especially, RCS and distance from target are not radar performance defined parameters but external parameters. Therefore radar deployment position that large RCS can be observed and target to radar distance should be considered in parallel to improve target detection probability. In this paper, RCS pattern of SCUD-B ballistic missile is calculated, received power is analyzed based on radar deployment position during ballistic missile trajectory and methode for optimum radar deployment position to improve target detection probability is suggested.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.145-151
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• 2003

The domestic and the industry wastes which mainly come out of human life activities have been usually processed mainly by the incineration method and/or the method of reclamation. The method of reclamation, specially open dumping, has caused significant environmental pollution problems on the local or regional soil and groundwater system by leachate. Therefore, to investigate the 3-D structure characteristics of environmental pollution area is one of the hot subjects. We applied dipole-dipole method of electrical resistivity survey to investigate 3-D environmental contamination characteristics of the Noeun landfill area. For electrical resistivity survey, the line for measurements was established parallel to the main boundary of the Noeun landfill, for effective investigation of the whole landfill area. The result shows that the uppermost layer of the Noeun landfill is believed to be stabilized completely, based on the result of electrical resistivity values. However, the lowest layer of the Noeun landfill was partially polluted by leachate. Therefore, the electrical resistivity survey method is believed to be the one of the most effective methods to investigate three-dimensional distribution of leachate occurred in the lower part of landfill area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.585-593
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• 2017

In this paper, we propose a deblocking filter hardware architecture for low-power HEVC (High-Efficiency Video Coding) in-loop for mobile systems. HEVC performs image compression on a block-by-block basis, resulting in blockage of the image due to quantization error. The deblocking filter is used to remove the blocking phenomenon in the image. Currently, UHD video service is supported in various mobile systems, but power consumption is high. The proposed low-power deblocking filter hardware structure minimizes the power consumption by blocking the clock to the internal module when the filter is not applied. It also has four parallel filter structures for high throughput at low operating frequencies and each filter is implemented in a four-stage pipeline. The proposed deblocking filter hardware structure is designed with Verilog HDL and synthesized using TSMC 65nm CMOS standard cell library, resulting in about 52.13K gates. In addition, real-time processing of 8K@84fps video is possible at 110MHz operating frequency, and operation power is 6.7mW.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2067-2075
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• 2017

Lately big data processing is considered as an emerging issue. As a huge amount of data is generated, data processing capability is getting important. In processing big data, both Hadoop distributed file system and unstructured date processing-based NoSQL data store are getting a lot of attention. However, there still exists problems and inconvenience to use NoSQL. In case of low volume data, MapReduce of NoSQL normally consumes unnecessary processing time and requires relatively much more data retrieval time than RDBMS. In order to address the NoSQL problem, in this paper, an interworking scheme between NoSQL and the conventional RDBMS is proposed. The developed auto-mapping scheme enables to choose an appropriate database (NoSQL or RDBMS) depending on the amount of data, which results in fast search time. The experimental results for a specific data set shows that the database interworking scheme reduces data searching time by 35% at the maximum.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1169-1181
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• 1994

The Gamma Network contains the redundant path thereby is provides the ability to tolerate the faults occured. However, in case of identical the source and destination number, only a single path exists, therefore there is no way of connecting for the fault situation. In addition, for the dynamic packet routing strategy, it shoed perform backtracking analysis to find the redundant path. In this paper we proposed a new network, Dual Network, to resolve these drawbacks. The Dual Network uses switching elements about the same network size as the Gamma Network except first and last stage, and it is more efficient than the Gamma Network, for it has reduced the switching stage by one. And since is used a destination tag routing scheme for the control algorithm, it has on advantage of becoming of simpler and faster routing control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5148-5155
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• 2013

The induced voltage on the telecommunication cable generated by nearby electric railway system may bring about telecommunication errors and safety accidents. In order to reduce the induced voltage and to achieve communication reliability, the effect of the shield cables and the recent double-track railway systems on the inductive interference should be investigated. This paper analyzes the parameters which seriously influence the induced voltage on the telecommunication cables which run parallel with a AT-fed electric railway line, and provides a simulation-based approach to estimate the amount of the induced voltage. Simulation results indicate that the induced noise voltage generated by a double-track railway decreases by 18 % compared to that generated by a single-track railway, showing the screening effect by nearby track. The induced noise voltages on the 50%-shielded cable and 15%-shielded cable decrease to 1/8 and 1/15 of the induced voltage on the non-shielded cable, respectively. A meaningful shield effect is achieved and the induced voltage is minimized by the double-track railway and the shielded cable.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.1
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• pp.51-65
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• 2002

This paper presents a design method of the neural network-based controller using an indirect adaptive control method to deal with an intelligent control for chaotic nonlinear systems. The proposed control method includes the identification and control Process for chaotic nonlinear systems. The identification process for chaotic nonlinear systems is an off-line process which utilizes the serial-parallel structure of multilayer neural networks and simple state space neural networks. The control process is an on-line process which uses the trained neural networks as the system model. An error back-propagation method was used for training of identification and control for chaotic nonlinear systems. The performance of the proposed neural network controller was evaluated by application to the Duffing equation and the Lorenz equation, and the proposed controller was compared with other neural network-based controllers by computer simulations.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.31-39
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• 2016

This paper is studied on the effect of the bolt joint stiffness on the Thrust Measurement Stand(TMS). TMS is a test stand for thrust performance of the propulsion system, which depends on two factors: The $1^{st}$ is the parallel degree between directions of the thrust vector and action lines of the corresponding measuring load cells for the vector, and the $2^{nd}$ is the orthogonality between action lines of the measuring load cells. Therefore, it is essential to maintain the original shape of the TMS under operating conditions. In this paper, it is examined how the geometric tolerance of the bolt joints and threads of the load cell trains affect the performance of the TMS. Also, some techniques to overcome related problems are proposed.