• 한국정보통신학회논문지
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• 제12권10호
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• pp.1717-1722
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• 2008

스트레스 정도를 측정하기 위한 다양한 도구들이 많이 사용되고 있다. 스트레스 측정에는 심리측정과 생체측정이 있다. 어느 한쪽만을 고려하였을 경우 주관적이거나 객관적 결여가 발생한다. 그 문제점을 보완하기 위해 두 측정을 혼합한 새로운 스트레스 지수가 필요하다. 개인적 특성에 따라 측정 결과도 다양하게 나타나지만, 현재 사용되고 있는 측정도구를 바탕으로 한 일반적인 경우를 고려하여 연구하였다. 심리와 생체 측정 도구를 통해서 얻어지는 지수를 이용하여 통합적인 스트레스 지수를 얻는다. 그래서 임의로 4가지의 스트레스 측정도구를 사용한다. 각 측정도구에서 나온 결과에 대한 멀티지수가 나타나는데, 그 지수들을 각각 좌표평면에 나타내어 스트레스에 대한 균형성과 편향성을 분석하고 진단한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.459-459
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• 2022

물수지의 불균형으로 발생되는 가뭄은 장기간에 걸쳐 넓은 규모로 발생되는 자연재해로서, 농업 및 산업에 직접 피해와 다양한 상품에 대한 공급 부족으로 인한 가격 상승 등의 간접 피해를 야기하는 재해이다. 이러한 가뭄을 정량적으로 평가하기 위하여 기상 요인(강수, 기온), 농업 요인(식생), 수문 요인(증발산, 토양수분) 등과 같은 설명 변수를 기초로 하는 많은 가뭄지수들이 개발되어 왔다. 대표적인 가뭄지수에는 Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Palmer Drought Severity Index (PDSI), Soil Water Deficit Index (SWDI), Vegetation condition index (VCI), Temperature Condition Index (TCI), Vegetation Health Index (VHI), Scaled Drought Condition Index (SDCI), Integrated Crop Drought Index (ICDI) 등이 있다. 본 연구는 최근 개발된 통합작물가뭄지수(ICDI)를 통해 미국 옥수수의 약 90%를 생산하는 농업지역인 미국 콘벨트의 가뭄 특성을 분석하고자 한다. ICDI는 기상 요인(강우량 및 지표면 온도), 수문학적 요인(잠재 증발산 및 토양수분), 식생 요인(강화식생지수(Enhanced Vegetation Index, EVI))의 조합을 통해 지표면의 건조·습윤 상태 및 식생의 건강 상태를 설명하는 가뭄지수이다. 2004년부터 2019년까지 주요 콘벨트 지역인 일리노이, 인디애나, 아이오와를 대상으로 가뭄분석을 실시하였으며, 옥수수 수확량 아노말리와의 상관성을 분석하였다.

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 2008년도 발표논문집
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• pp.216-219
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• 2008

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 2008년도 발표 논문집 제17권
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• pp.216-219
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• 2008

• Journal of the Optical Society of Korea
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• 제11권1호
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• pp.40-43
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• 2007

We propose a taper-underlaid spot-size converter (TU-SSC) with an offset which consists of two vertically stacked taper layers. The designed TU-SSC reduces coupling loss of a high index-contrast waveguide with $1.5%{\Delta}$ to a single mode fiber from 1.5 dB to 0.27 dB. We also considered the effects of mask misalignment in the fabrication process of TU-SSC, and optimized the design of TU-SSC so that the additional loss of TU-SSC for the mask misalignment of $3{\mu}m$ in the photo-lithography process was as low as 0.13 dB.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.162-165
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• 2008

A novel planar lightwave circuit(PLC) triplexer using a three-waveguide interferometer(TWI) is proposed and examined using the transfer matrix and the beam propagation methods. The proposed triplexer consists of two three-waveguide couplers and three waveguides connecting the couplers. Simulation for the TWI triplexer shows the excess losses of 0.03 dB and 0.94 dB with the crosstalks of -22.3 dB and -14.5 dB in reception, respectively, for the wavelength of 1490- and 1550-nm, while showing the excess loss of 1.75 dB in transmission for the wavelength of 1310 nm. The proposed design shows compact feature as short as 11.5 mm for the refractive-index contrast of 0.45%.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.693-694
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• 2015

While urban regeneration projects are currently under active execution in several old cities in Korea, there are few projects to improve the quality of life of rural communities. Considering the decline of the SOC system, deterioration of housing, and degeneration of economic feasibility, the purpose of this study is to provide solutions to realize an improved economic and social environment of rural communities through an integrated management system for traffic safety and water management systems. Therefore, this research used an Entity-Relationship Diagram to construct an integrated system for traffic safety and water management systems for Chungcheong rural communities. The ERD is prepared by depicting 7 relationships for 13 entities, including traffic accidents and agricultural products, and 26 attributes, including soil moisture and underflow storage. Consequently, it will be possible to set up a decision-making support system that can analyze and evaluate the regeneration index, technology, and management of the systems for Chungcheong rural communities, based on supplier and user perspectives

• Current Optics and Photonics
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• 제3권4호
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• pp.298-303
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• 2019

We propose a photonic quasi-crystal fiber (PQF) for supporting up to 14 orbital angular momentum (OAM) modes with low and ultra-flat dispersion characteristics over the C+L bands. The designed PQF which consists of a large hollow center and quasi structural small air holes in the clad region exhibits low confinement losses and a large effective index separation (>$10^{-4}$) between the vector modes. This proposed fiber could potentially be exploited for mode division multiplexing and other OAM mode applications in fibers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.3182-3203
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• 2023

With the growing adoption of cloud-based technologies, maintaining the privacy and security of cloud data has become a pressing issue. Privacy-preserving encryption schemes are a promising approach for achieving cloud data security, but they require careful design and implementation to be effective. The integrated approach to cloud data security that we suggest in this work uses CogniGate: the orchestrated permissions protocol, index trees, blockchain key management, and unique Opacus encryption. Opacus encryption is a novel homomorphic encryption scheme that enables computation on encrypted data, making it a powerful tool for cloud data security. CogniGate Protocol enables more flexibility and control over access to cloud data by allowing for fine-grained limitations on access depending on user parameters. Index trees provide an efficient data structure for storing and retrieving encrypted data, while blockchain key management ensures the secure and decentralized storage of encryption keys. Performance evaluation focuses on key aspects, including computation cost for the data owner, computation cost for data sharers, the average time cost of index construction, query consumption for data providers, and time cost in key generation. The results highlight that the integrated approach safeguards cloud data while preserving privacy, maintaining usability, and demonstrating high performance. In addition, we explore the role of differential privacy in our integrated approach, showing how it can be used to further enhance privacy protection without compromising performance. We also discuss the key management challenges associated with our approach and propose a novel blockchain-based key management system that leverages smart contracts and consensus mechanisms to ensure the secure and decentralized storage of encryption keys.

• Journal of Information Processing Systems
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• 제10권4호
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• pp.628-645
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• 2014

In past few years, distributed hash table (DHT)-based P2P systems have been proven to be a promising way to manage decentralized index information and provide efficient lookup services. However, the skewness of users' preferences regarding keywords contained in a multi-keyword query causes a query load imbalance that combines both routing and response load. This imbalance means long file retrieval latency that negatively influences the overall system performance. Although index replication has a great potential for alleviating this problem, existing schemes did not explicitly address it or incurred high cost. To overcome this issue, we propose, in this paper, an integrated solution that consists of three replication schemes to alleviate query load imbalance while minimizing the cost. The first scheme is an active index replication that is used in order to decrease routing load in the system and to distribute response load of an index among peers that store replicas of the index. The second scheme is a proactive pointer replication that places location information of each index to a predetermined number of peers for reducing maintenance cost between the index and its replicas. The third scheme is a passive index replication that guarantees the maximum query load of peers. The result of simulations indicates that the proposed schemes can help alleviate the query load imbalance of peers. Moreover, it was found by comparison that our schemes are more cost-effective on placing replicas than PCache and EAD.