• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.15-22
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• 2020

In this study, we propose an improvement method that can create U-Net model which detect fine concrete cracks by applying a weighted loss function. Because cracks in concrete are a factor that threatens safety, it is important to periodically check the condition and take prompt initial measures. However, currently, the visual inspection is mainly used in which the inspector directly inspects and evaluates with naked eyes. This has limitations not only in terms of accuracy, but also in terms of cost, time and safety. Accordingly, technologies using deep learning is being researched so that minute cracks generated in concrete structures can be detected quickly and accurately. As a result of attempting crack detection using U-Net in this study, it was confirmed that it could not detect minute cracks. Accordingly, as a result of verifying the performance of the model trained by applying the suggested weighted loss function, a highly reliable value (Accuracy) of 99% or higher and a harmonic average (F1_Score) of 89% to 92% was derived. The performance of the learning improvement plan was verified through the results of accurately and clearly detecting cracks.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.55-66
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• 2018

Since existing server-based authentications use vulnerable password-based authentication, illegal leak of personal data occurs frequently. Since this can cause illegal ID compromise, alternative authentications have been studied. Recently token-based authentications like OAuth 2.0 or JWT have been used in web sites, however, they have a weakness that if a hacker steals JWT token in the middle, they can obtain plain authentication data from the token, So we suggest a new authentication method using the verification token of authentic code to encrypt authentication data with effective time. The verification is to compare an authentication code from decryption of the verification-token with its own code. Its crypto-method is based on do XOR with ECDH session key, which is so fast and efficient without overhead of key agreement. Our method is outstanding in preventing the personal data leakage.

• Journal of Convergence Society for SMB
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• v.2 no.2
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• pp.35-41
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• 2012

The rapid development of cloud computing and mobile internet service changes to an mobile cloud service environment that can serve and pay computing source that users want anywhere and anytime. But when user misses mobile device, the respond to any threat like user's personal information exposal is insufficient. This paper proposes cloud service access control model to provide secure service for mobile cloud users to other level users. The proposed role-based model performs access authority when performs user certification to adapt various access security policy. Also, the proposed model uses user's attribute information and processes before user certification therefore it lowers communication overhead and service delay. As a result, packet certification delay time is increased 3.7% and throughput of certification server is increased 10.5%.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.463-463
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• 2011

농업은 다른 산업과 달리 원천적으로 기후 조건과 변화에 크게 좌우되는 분야로, 기후변화로 인한 영향에 가장 민감한 분야이다. 안정적이고 지속적인 농작물 생산을 위해서는 기후변화가 농업수자원에 미치는 영향에 대하여 정확히 파악하고, 이로 인해 발생할 수 있는 부정적 효과를 최소화하기 위한 연구가 필요하다. 즉 기온 상승, 강수량 및 강우강도 변화 및 일조시간의 변화 등의 기후변화에 따른 농업수자원에 미치는 영향에 대한 평가가 필요하다. 기후변화가 관개용수에 미치는 영향은 기온 상승과 강수량 증가로 크게 나누어 볼 수 있다. 기온상승은 증발산량 증가로 이어져 관개용수 증가의 원인이 된다. 강수량의 증가는 관개용수를 감소의 원인이 될 수 있지만, 계절별 강우 편차 및 강우 강도의 변화는 유효우량의 감소의 원인이 될 수 있다. 이는 관개기의 농업용수의 안정적 공급과 관리의 어려움이 예상되어 결과적으로 농업용수의 안정성을 위협받을 수도 있다. 즉, 전체 수자원에 큰 비중을 차지하고 있는 논벼의 순용수량에 있어서 기후변화가 미치는 영향에 대한 연구가 필요하다. 또한 농업용수개발과 수자원의 효율적인 관리계획 수립을 위해서는 기후변화에 따른 농업용수 수요분석이 이루어져야 한다. 따라서 본 연구에서는 기후변화 시나리오에 따른 순용수량을 산정하고, 이를 빈도분석하여 논벼의 수요량 변화를 분석하고자 하였다. 이를 위하여 이를 위하여 먼저 CGCM3.1 (Coupled Global Climate Model Ver. 3.1) 및 LARS-WG (Long Ashton Research Station Weather Generator)를 이용하여 2011년부터 2100년까지의 A1B, A2 및 B1 시나리오별로 기상자료를 생성하였다. 이를 바탕으로 물수지 방법을 이용하여 논에서의 순용수량을 산정하고, 한발기준 10년빈도 순용수량을 산정하여 논벼의 수요량을 분석하였다. 연구 결과는 향후 기후변화로 인한 농업용수 변화를 파악하고 전망함으로써, 추후 발생할 수 있는 부정적 효과를 최소화하기 위한 대응 전략 및 농업수자원 정책의 기초 자료로 활용될 수 있을 것으로 판단된다.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.37-48
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• 2008

VoIP service is a transmission of voice data using SIP protocol on IP based network, The SIP protocol has many advantages such as providing IP based voice communication and multimedia service with cheap communication cost and so on. Therefore the SIP protocol spread out very quickly. But, SIP protocol exposes new forms of vulnerabilities on malicious attacks such as Message Flooding attack and protocol parsing attack. And it also suffers threats from many existing vulnerabilities like on IP based protocol. In this paper, we propose a new Virtual Proxy Server system in front of the existed Proxy Server for anomaly detection of SIP attack and stateful management of SIP session with enhanced security. Based on stateful virtual proxy server, out solution shows promising SIP Message Flooding attack verification and detection performance with minimized latency on SIP packet transmission.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.951-954
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• 2005

This paper presents a study on the accuracy position Controller design for the Composite Smoke Bomb Rotational driving system using a BLDC servo motor. Function of Smoke Bomb is blind in the enermy's sight so that need to high response. The BLDC servo motor controller was designed with DSP(TMS320VC33), IGBT(Insulated Gate Bipolar. Transistor), IGBT gate driver and CPLD(EPM7128). This paper implements those control with vector control and MIN-MAX PWM. Vector control requires information about rotor positions, a resolver should be used to achieve that. The main controller is implemented with a TMS320VC33 high performance floating-point DSP(Digital Signal Process) and PWM Generator is embodied using EPM7128.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.989-998
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• 2005

Information systems are today becoming larger and mostly broadband-networked. This exposes them at a higher risk of intrusions and hacking than ever before. Of the technologies developed to meet information system security needs, risk analysis is currently one of the most actively researched areas. Meanwhile, due to the extreme diversity of assets and complexity of network structure, there is a limit to the level of accuracy which can be achieved by an analysis tool in the assessment of risk run by an information system. Also, the results of a risk assessment are most oftennot up-to-date due to the changing nature of security threats. By the time an evaluation and associated set of solutions are ready, the nature and level of vulnerabilities and threats have evolved and increased, making them obsolete. Accordingly, what is needed is a risk analysis tool capable of assessing threats and propagation of damage, at the same time as security solutions are being identified. To do that, the information system must be simplified, and intrusion data must be diagrammed using a modeling technique this paper, we propose a modeling technique information systems to enable security risk analysis, using SPICE and Petri-net, and conduct simulations of risk analysis on a number of case studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.558-565
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• 2021

The Republic of Korea Navy has deployed naval fleets in the East, West, and South seas to effectively respond to threats from North Korea and its neighbors. However, it is difficult to allocate proper missions due to high uncertainties, such as the year of introduction for the ship, the number of mission days completed, arms capabilities, crew shift times, and the failure rate of the ship. For this reason, there is an increasing proportion of expenses, or mission alerts with high fatigue in the number of workers and traps. In this paper, we present a simulation model that can optimize the assignment of naval vessels' missions by using a continuous time absorbing Markov chain that is easy to model and that can analyze complex phenomena with varying event rates over time. A numerical analysis model allows us to determine the optimal mission durations and warship quantities to maintain the target operating rates, and we find that allocating optimal warships for each mission reduces unnecessary alerts and reduces crew fatigue and failures. This model is significant in that it can be expanded to various fields, not only for assignment of duties but also for calculation of appropriate requirements and for inventory analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.4
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• pp.287-295
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• 2022

As low altitude long-range artillery threat has been strengthened, the development of anti-artillery interception system to protect assets against its attacks will be kicked off. We view the defense of long-range artillery attacks as a typical dynamic weapon target assignment (DWTA) problem. DWTA is a sequential decision process in which decision making under future uncertain attacks affects the subsequent decision processes and its results. These are typical characteristics of Markov decision process (MDP) model. We formulate the problem as a MDP model to examine the assignment policy for the defender. The proximity of the capital of South Korea to North Korea border limits the computation time for its solution to a few second. Within the allowed time interval, it is impossible to compute the exact optimal solution. We apply approximate dynamic programming (ADP) approach to check if ADP approach solve the MDP model within processing time limit. We employ Shoot-Shoot-Look policy as a baseline strategy and compare it with ADP approach for three scenarios. Simulation results show that ADP approach provide better solution than the baseline strategy.

• The Korean Society of Law and Medicine
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• v.20 no.3
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• pp.235-262
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• 2019

While traditionally threatening human infectious diseases are decreasing, chronic diseases such as cancer and diabetes, including cardiovascular diseases, are spreading rapidly. Reflecting the characteristics of chronic diseases that are difficult to treat, the management of risk factors and the preparation of health promotion policies corresponding to them have emerged as important concerns around the world. Providing so-called multi-sector approach such as health promotion and disease prevention policy and solution for community response, The value of primary care is once again highlighted in the changed medical environment. As the existing medical delivery system has become difficult to cope with the people's desire for rapid aging, disease paradigm change, and quality of life improvement, European Union countries have made various efforts to improve the quality of their primary medical system, which provides continuous, com- prehensive and coordinated management. This paper examines the current status and problems of the healthcare delivery system in Korea, draws implications from the European Union examples related to the strengthening of primary care, and discusses the plans for establishing a patient-centered future medical delivery system.