• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8B
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• pp.502-508
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• 2007

This paper proposes a method to shut out all of the not certified network access packet by embodying the two-factor(MAC ADDRESS, ID/PASSWORD) authentication system. The Authenticating Gateway System takes over central server's policy and permit or hold up the packet by inherited policy. And checks the whether or not patched the OS version and getting influenced from computer virus. And takes the information about client's resources(H/W, S/W) without Agent in the client. That makes more stability of network operating circumstance and fast facing the attack from hackers. In the fixed mobile network circumstance, This method provides more simplicity and less expenses than IEEE802.1x authentication system(cisco nac).

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.37-46
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• 2005

In Processing many operations based on distributed environment, it is very important to support the reliability of resources. Providers of resources generally adapt the structure of server-replication to support the reliability of services. Tn server side, it maintains replicas. duplicated server objects. In the structure of this replication, service of stable replica is very important. Therefore the structure to diagnosis the fault of such replica is required. In this Paper, we suggested an effective PUSH fault management algorithm based on PUSH monitoring style of CORBAto overcome weak points of the PULL monitoring style of the replication management system in the distributed object system. Outcomes of the suggested PUSH fault monitoring style were better than other system. We confirmed valuable result in the workloads and timeout-rates.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.574-578
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• 2016

For the last few decades, much research has been tried to improve crop’s characteristics such as crop yield, quality, seeding period and environmental adaptability. In this paper, the effect of nanobubbles on the germination rate of barley seed is experimentally investigated. The air nanobubble was generated in water by gas-liquid mixing method. The results were shown that the mean diameter and concentration of nanobubble fabricated in DI water are 133 ㎚ and 8.59✕10⁸ particles/㎖, respectively. Also, the seed germination rate for the nanobubble water was approximately 40 % higher than that of pure water.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.151-153
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• 2016

모바일 디바이스의 성능 발전에 따라 높은 연산 능력을 요구하는 어플리케이션이 증가하고 있다. 3D 프로세싱, 영상 인코팅, 벡터 이미지 처리 등 연산량이 많아 기존에 데스크탑 컴퓨터에서 처리하던 작업들이 모바일 디바이스로 이전되고 있다. 그러나 모바일 디바이스 하드웨어의 발전 속도와 상이하게 사용자의 모바일 디바이스 교체 주기는 발전 속도를 따라잡지 못하고 있다. 따라서 추가적인 비용부담 없이 모바일 디바이스의 연산 능력을 향상시키기 위해 Mobile Cloud Computing(MCC)의 필요성이 대두되고 있다. MCC는 다수의 모바일 디바이스 리소스를 통합 관리하고 자원 서비스를 제공함으로써 작업 처리 및 자원 고가용성등의 성능 향상이 가능하다. 본 연구에서는 MCC 인프라 구축 방법인 Mobile Resource Integration(MRI)와 MRI에 적용되는 오프로드 방법을 제안한다. 모바일 디바이스로만 구성된 MRI는 분산된 모바일 디바이스로 작업를 분할 전송 처리는 방법이다. 이를 통해 중거리 및 원거리 통신망 연결이 어려운 경우에 단일 모바일 디바이스의 작업 처리 대비 높은 향상 속도를 보인다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2992-2998
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• 2013

The future mobile communication system can support not only voice but also multimedia applications such as data, image and video. It requires greater resources than the voice-oriented mobile system. We propose user and sub-channel priority based resource allocation for mobile multimedia services in the OFDMA systems. Our method is able to guarantee QoS continuity of realtime services and carry the maximum number of non-realtime subscriber. Simulation is focused on total throughput and blocking rate. The simulation results show that our proposed method provides a better performance than the conventional method.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.23-26
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• 2002

The generation of wastewood is currently about 40% level of the amount of domestic wood use. When the rate of wood self-supply is considered, the recycling of wastewood in wood panel products industry should be encouraged. This study was evaluated the performance of particleboard (PB) made from wastewood. PBs were manufactured with the synthesized urea-formaldehyde resin at 5 minutes hot-press time, and at 162℃ press temperature with 6 percent resin solids level on an ovendry wastewood particle weight basis. The PBs were tested by the procedure of ASTM D 1037. Test results exceeded the minimum strength requirement according to KS F 3104 Particleboard type 8.0. The PB's performance showed that wastewood is suitable raw material for PB.

• Resources Recycling
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• v.20 no.5
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• pp.16-33
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• 2011

Waste electrical and electronic equipment(WEEE or E-waste) is one of the fastest growing waste stream in Korea. The proper management of such equipment has become of major concern for solid waste professionals because of the large growth of the waste stream and the presence of a myriad of toxic materials with in it. In this paper in order to review the recycling system and recycling industries of the E-waste in Korea, the main frame concerning recycling of "Act on the Resources Recycling of Waste Electrical Electronic Equipment(WEEE) and End-of-life vehicles", recycling system, current recycling status, estimation of the E-waste generation, material flow of the E-waste, economics of PCB and recycling industries of the E-waste were surveyed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1104-1113
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• 2014

Future combat systems can be represented as the NCW (Network Centric Warefare), which is based on the concept of Sensor-to-Shooter. A wireless video sensor networking technology, one of the core components of NCW, has been actively applied for the purpose of tactical surveillance. In such a surveillance sensor network, multi-composite sensors, especially consisting of image sensors are utilized to improve reliability for intrusion detection and enemy tracing. However, these sensors may cause a problem of requiring very high network capacity and energy consumption. In order to alleviate this problem, this paper proposes an image data transmission scheme based on resource reservation. The proposed scheme can make it possible to have more reliable image data transmission by choosing proper multiple interfaces, while trying to control resolution and compression quality of image data based on network resource availability. By the performance analysis using NS-3 simulation, we have confirmed the transmission reliability as well as energy efficiency of the proposed scheme.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.151-160
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• 2005

The exponential growth of Web users requires the web serves with high expandability and reliability. It leads to the excessive transmission traffic and system overload problems. To solve these problems, cluster systems are widely studied. In conventional cluster systems, when the request size is large owing to such types as multimedia and CGI, the particular server load and response time tend to increase even if the overall loads are distributed evenly. In this paper, a cluster system is proposed where each Web server in the system has different contents and loads are distributed efficiently using the Web server resource information such as CPU, memory and disk utilization. Web servers having different contents are mutually connected and managed with a network file system to maintain information consistency required to support resource information updates, deletions, and additions. Load unbalance among contents group owing to distribution of contents can be alleviated by reassignment of Web servers. Using a simulation method, we showed that our method shows up to $50\%$ about average throughput and processing time improvement comparing to systems using each LC method and RR method.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.171-178
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• 2016

Extensive efforts from all over the world have been made to solve energy problems, such as high oil prices, global warning due to the depletion of oil. Among them, biofuel has been drawing attention as a clean energy, which can replace fossil fuels. However, conventional biofuels were often converted from eatable biomass such as sugar cane, corn and soy which should be replaced with uneatable biomass. In this study, a techno-economical evaluation of the gasification of biomass waste with mixed alcohol synthesis process was performed. Considering available domestic biomass wastes, a 2000 ton/day conversion plant were assumed to produce 533000 L/day ethanol. Also, financial data from previous studies were evaluated and used and economical sensitivities with various operation conditions were established. Economic analysis were conducted by the payback period and internal rate of return (IRR) and net present value (NPV). Sensitivity analyses of raw material costs, initial investment, the major process cost, ethanol price changes and operating costs were all performed.