• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.239-248
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• 2012

VANET (Vehicular Ad-hoc Network) is a type of MANET (Mobile Ad-hoc Network) which is the next-generation networking technology to provide communication between vehicles or between vehicle and RSU (Road Side Unit) using wireless communication. In VANET system, a vehicle accident is likely to cause awful disaster. Therefore, in VANET environment, authentication techniques for the privacy protection and message are needed. In order to provide them privacy, authentication, and conditional, non-repudiation features of the group signature scheme using a variety of security technologies are being studied. In this paper, and withdrawal of group members to avoid frequent VANET environment is suitable for vehicles produced by the group administrator for a private signing key to solve the key escrow problem of a group signature scheme is proposed. We proposed a message batch verification scheme using Bloom Filter that can verify multiple messages efficiently even for multiple communications with many vehicles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1890-1910
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• 2013

Routing overlay offers an ideal methodology to improve the end-to-end communication performance by deriving a backup path for any node pair. This paper focuses on a challenging issue of selecting a proper backup path to bypass the failures on the default path with high probability for any node pair. For existing backup path selection approaches, our trace-driven evaluation results demonstrate that the backup and default paths for any node pair overlap with high probability and hence usually fail simultaneously. Consequently, such approaches fail to derive a robust backup path that can take over in the presence of failure on the default path. In this paper, we propose a three-phase RBPS approach to identify a proper and robust backup path. It utilizes the traceroute probing approach to obtain the fine-grained topology information, and systematically employs the grid quorum system and the Bloom filter to reduce the resulting communication overhead. Two criteria, delay and fault-tolerant ability on average, of the backup path are proposed to evaluate the performance of our RBPS approach. Extensive trace-driven evaluations show that the fault-tolerant ability of the backup path can be improved by about 60%, while the delay gain ratio concentrated at 14% after replacing existing approaches with ours. Consequently, our approach can derive a more robust and available backup path for any node pair than existing approaches. This is more important than finding a backup path with the lowest delay compared to the default path for any node pair.

• Journal of The Korean Society of Clinical Toxicology
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• v.4 no.2
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• pp.147-150
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• 2006

Neurotoxic shellfish poisoning (NSP) can result from eating filter-feeding shellfish carrying brevetoxins produced by the marine dinoflagellate Krenia brevis (formally Gymnodinium breve). Brevetoxins enhance sodium entry into cells via voltage-sensitive sodium channels and have an excitatory effect. The incubation period is three hours (range 15 minutes-18 hours). NSP is characterized by gastroenteritis combined with neurologic symptoms. Gastrointestinal (GI) symptoms include abdominal pain, nausea, diarrhea and burning pain in the rectum. Neurologic symptoms are paresthesia, reversal of hot and cold temperature sensation, myalgia, headache, vertigo, and ataxia. Other symptoms may include malaise, tremor, dysphagia, bradycardia, decreased reflexes, dilated pupils, seizure, and coma. The health problem caused by K. breviscan be associated with a red tide bloom. We encountered 3 cases of neurotoxic shellfish poisoning. They all presented with GI and neurologic symptoms andrecovered after conservative treatment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.2
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• pp.126-135
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• 2013

This study was performed to have an effect on control the growth of algae such as "Actinastrum fluviatile" which occurs frequently in the aquaculture tank using by a cold plasma, and it also would be expected to promote the growth of water plants due to active element causing OH radicals in the water. In addition, it was verified on the death rate as 99.9% on the scale protrusion of "Aeromonas hydrophila" as well as E. coli, especially, under extreme conditions more than 100 million pathogenic bacterium in the aqua pet tank, the ornamental fish had to act in a safe and healthy environment at over 98% death rate within 48 hours. It has been proven to give no affect on aerobic bacteria that exist in the filter or soil because there was no residual toxicity in the water tank. As the results, it will help to develop and apply on the sterilization device in other industries as well as aquarium organisms due to adopted energy-saving algorithm and reliability in use.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.567-573
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• 2019

DABF(Dissolve Air Flotation with Ball Filter) is developed as the DAF with the addition of a fiber ball at the lower part of the DAF. The DABF with a capacity of 4,500 ㎥/h was constructed at Gijang SWRO plant in Busan. Since the ball filter has high filtration rate, the loading rate of DABF was designed from 20 to 42 ㎥/h/㎡. When one DABF basin is in the back washing mode, the loading rate of other two DABF basins is increased to 42 ㎥/h/㎡. Turbidity at the BF outlet in DABF is <2 NTU at turbidity of 5-10 NTU at the BF inlet. If there is no algae bloom and turbidity is low in raw seawater, only BF in DABF is operated and meets <2 NTU at the BF outlet. Even if BF is operated at high hydraulic loading rates, no significant differential pressure increases and reduction in the turbidity removal rate is minimal in a day. Thus, DABF is the pre-treatment technology that provides stable water quality even with BF onlyoperation without DAF operation. Compared with the DAF, DABF requires additional facilities such as valves, piping, and drainage systems for backwashing the BF. But in terms of footprint and operating costs, DABF has more advantages than DAF. With DABF application, the load of the downstream filtration equipment is decreased so that the capacity of the filtration equipment can be reduced. Also, if the downstream filtration equipment is to be maintained the same regardless of DABF, the operating cost of DABF is less than DAF.

• Annual Conference on Human and Language Technology
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• 2018.10a
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• pp.69-74
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• 2018

최근 빅 데이터와 인공지능의 발달과 함께 감성 분석에 대한 연구가 활발해지고 있다. 더불어 감성 분석을 위한 긍/부정 어휘가 풍부한 텍스트 문서들에 대한 수집의 필요성도 높아지고 있다. 본 논문은 긍/부정어휘가 풍부한 텍스트 문서들을 수집하는 기존의 수집 방법에 대한 문제점에 대하여 해결방안을 제시한다. 기존의 수집 방법으로 일단 모든 URL들을 저장하고 필터링 과정을 거쳐 긍/부정 어휘가 풍부한 텍스트 문서들을 수집하고자 한다면 불필요한 텍스트 문서 저장과 필터링 과정에서 메모리와 시간을 낭비하게 된다. 기존의 수집 방법에 블룸 필터라는 자료구조를 적용시켜 메모리와 시간을 낭비하게 되는 문제점을 해결하고자 한다.

• Journal of Environmental Science International
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• v.26 no.5
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• pp.685-689
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• 2017

Aquatic plants serve the crucial function of helping to balance water reservoir ecosystem, as they filter and remove major minerals required for algal growth such as nitrogen, ammonia, and nitrates. Aquatic plants provide food, shade, and protection for the aquatic biome in and around the reservoir. Thus, it is important to accurately determine the existence and areal extent of the aquatic plants. In the present study drone-based facilities were used for this purpose. In the Muncheon water reservoir, Gyeongbuk, the Normalized Difference Vegetation Index (NDVI) and Surface Algal Bloom Index (SABI) were used to determine the existence status of the aquatic plants. The data so obtained exhibited reasonable accuracy; drone-based facilities can be used in future to identify the areal extent of aquatic plants.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.16-20
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• 2010

최근 급격히 발전하는 RFID(Radio Frequency Identification)나 USN(Ubiquitous Sensor Network)과 같은 무선환경은 태그(tag)와 리더(reader)간에 라디오 주파수를 이용하여 통신한다. 이러한 통신은 그 특성상 주파수 범위내의 다른 태그나 리더들 또한 이들의 통신내용을 들을 수 있다. 따라서 이렇게 도청된 정보는 악의적인 사용자에 의해 여러 가지 보안 공격을 야기할 수 있다. 반면 이러한 형태의 공격에 대해 대부분의 보안프로토콜은 외부의 공격에 주목하는 반면, 같은 알고리즘으로 통신하는 내부자의 공격, 특히 참여(entry)객체의 프라이버시정보는 이러한 프로토콜에서 보호되기 어렵다. 따라서 본 논문에서는 무선환경에서 최근 이슈가 되고 있는 불룸필터(bloom filter)를 이용하여 개인의 프라이버시 정보를 효과적으로 보호할 수 있는 기법을 제안하고 불룸필터를 확장 적용해서 그 성능을 개선하여 좀 더 효율적인 프라이버시 보호 기법을 설계하고자한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.270-273
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• 2016

암호데이터 중복제거 기술이란 클라우드 서버에 전송된 데이터를 기존의 클라우드 서버에 저장된 데이터와 비교하여 데이터의 중복된 저장을 방지하는 기술이다. 이러한 데이터 중복제거 기술은 다양한 보안 위협이 발생하는데, 이 중 소유권 위조 공격은 원본 데이터를 소유하지 않은 공격자가 데이터의 소유권을 획득하여 클라우드 스토리지에 저장된 데이터를 취득할 수 있는 위협이다. 이러한 위협을 해결하기 위해 암호화 기술을 적용한 여러 기술들이 제안되어왔지만 과도하게 많은 통신 횟수와 연산량으로 인해 효율성이 떨어지는 문제가 존재한다. 따라서 본 논문에서는 클라우드 스토리지에 저장되는 데이터의 기밀성과 무결성을 보장하며, 연산량과 통신량 측면에서 효율적인 암호데이터 중복제거 기술을 제안한다.

• Journal of Information Processing Systems
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• v.20 no.2
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• pp.252-262
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• 2024

The multi-hop wireless sensor network (WSN) suffers from energy limitation and eavesdropping attacks. We propose a simple and energy-efficient convergecast mechanism using inter-flow random linear network coding that can provide confidentiality to the multi-hop WSN. Our scheme consists of two steps, constructing a logical tree of sensor nodes rooted at the sink node, with using the Bloom filter, and transmitting sensory data encoded by sensor nodes along the logical tree upward to the sink where the encoded data are decoded according to our proposed multi-hop network coding (MHNC) mechanism. We conducted simulations using OMNET++ CASTALIA-3.3 framework and validated that MHNC outperforms the conventional mechanism in terms of packet delivery ratio, data delivery time and energy efficiency.