• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.430-434
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• 2010

OECD등 국제기구와 현재 국회에 계류 중인 물 관리기본법 제정(안)등에서 물 이용자에 대한 수익자 부담 원칙을 요구하고 있어, 농업용수의 대부분을 관리하고 있는 한국농어촌공사 관리지역의 농업용수 이용료(구 조합비) 면제에 대한 문제점이 제기되고 일부 전문가들 사이에서도 농업용수 이용료 부과의 필요성이 지속적으로 제기되고 있는 실정이다. 이러한 시점에서 과거 농업용수 이용료(구 조합비) 부과 및 면제의 역사를 살펴보고, 농업용수 및 농업 농촌의 특성을 고려한 농업용수 이용에 따른 수익자 부담원칙에 대하여 검토하였다. 농업용수 이용료는 1908년 수리조합이 시작된 이후 1999년까지 조합비 형태로 부과하다가 2000년 농업용 수관련 3개 기관이 공사로 통합하면서 면제가 되었고, 지난 10년 동안 외부(OECD 등)의 요구뿐만 아니라 내부적으로도 농업용수관리 비용증가로 인한 이용료 부과가 필요하다는 주장이 제기되었다. 한편 이용료 부과시 농업인 경제적 부담증가, 농업용수관리 정책의 혼선, 농업인 반발로 인한 사회문제화, 이용료 징수의 실효성 및 실익성에 대한 문제가 발생될 수 있다. 따라서 농업용수이용에 대하여 단순히 수익자 부담원칙 준수를 요구만 할 것이 아니라 면제에 대한 역사적, 사회경제적인 배경과 농업 농촌의 특성을 이해하고 국내외적으로 대두되는 수익자 부담원칙에 대하여 어떻게 합리적인 방법과 사회적인 합의를 이끌어 낼 것인가 장기적인 연구와 검토가 필요하다. 또한 비용부담측면만이 아니라 농업인의 물 관리 참여(PIM, Participatory Irrigation Management)등을 통한 수익자부담 원칙 달성 및 비용절감을 유도할 수 있는 제 3의 방안을 찾아야 한다.

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.199-204
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• 2006

The kernel hardening function is necessary in terms of kernel stability to reduce the system error or panic due to the kernel code error that is made by program developer. But, the traditional kernel hardening method is difficult to implement and consuming high cost. The suggested kernel hardening function that makes high availability system by changing the panic() function of inside kernel code guarantees normal system operation by recovering the incorrect address of the kernel stack frame. We experimented the kernel hardening function at the network module of the Linux by forcing panic code and confirmed the proposed design mechanism of kernel hardening is working well by this experiment.

• Industrial Engineering and Management Systems
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• v.12 no.2
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• pp.74-84
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• 2013

Modern companies have been facing devastating impacts from unexpected events such as demand uncertainties, natural disasters, and terrorist attacks due to the increasing global supply chain complexity. This paper proposes a multi stage logistic network model under disruption risk. To formulate the problem practically, we consider the effect of continuity rate, which is defined as a percentage of ability of the facility to provide backup allocation to customers in the abnormal situation and affect the investments and operational costs. Then we vary the fixed charge for opening facilities and the operational cost according to the continuity rate. The operational level of the company decreases below the normal condition when disruption occurs. The backup source after the disrup-tion is recovered not only as soon as possible, but also as much as possible. This is a concept of the business continuity plan to reduce the recovery time objective such a continuity rate will affect the investments and op-erational costs. Through numerical experiments, we have shown the proposed idea is capable of designing a resilient logistic network available for business continuity management/plan.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.6
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• pp.770-778
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• 2012

In this paper, we propose a multi-path construction scheme to improve the survivability of a multicast session in military hybrid networks. A military hybrid network consists of a static backbone network and multiple mobile stub networks where some nodes are frequently susceptible to be disconnected due to link failure and node mobility. To improve the survivability of multicast sessions, we propose a construction scheme of ${\kappa}$ redundant multi-paths to each receiver. In order to take account of different characteristics of static and mobile networks, we propose quite different multi-path setup approaches for the backbone and stub networks, respectively, and combine them at the boundary point called gateway. We prove that our proposed scheme ensures that each receiver of a multicast session has ${\kappa}$ redundant paths to the common source. Through simulations, we evaluate the performance of the proposed schemes from three aspects : network survivability, recovery cost, and end-to-end delay.

• Journal of Information Technology Services
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• v.7 no.1
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• pp.117-130
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• 2008

Multi-attribute risk assessments provide a useful framework for systematic quantitative risk assessment that the security manager can use to prioritize security requirements and threats. In the first step, the security managers identify the four significant outcome attributes(lost revenue, lost productivity, lost customer, and recovery cost). Next. the security manager estimates the frequency and severity(three points estimates for outcome attribute values) for each threat and rank the outcome attributes according to AHP(Analytic Hierarchy Process). Finally, we generate the threat index by using muiti-attribute function and make sensitivity analysis with simulation package(Crystal Ball). In this paper, we show how multi-attribute risk analysis techniques from the field of security risk management can be used by security managers to prioritize their organization's threats and their security requirements, eventually they can derive threat index. This threat index can help security managers to decide whether their security investment is consistent with the expected risks. In addition, sensitivity analysis allows the security manager to explore the estimates to understand how they affect the selection.

• Journal of Power Electronics
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• v.15 no.2
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• pp.346-355
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• 2015

On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters ($K_p$, $K_i$ and $K_d$) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient $K_d$ is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.158-164
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• 2016

In this paper, a high frequency flyback type zero voltage soft switching PWM DC-DC converter using IGBTs is proposed. Effective applications for this power converter can be found in auxiliary power supplies of rolling stock transportation and electric vehicles. This power converter is basically composed of active power switches and a flyback high frequency transformer. In addition to these, passive lossless snubbers with power regeneration loops for energy recovery, consisting of a three winding auxiliary high frequency transformer, auxiliary capacitors and diodes are introduced to achieve zero voltage soft switching from light to full load conditions. Furthermore, this power converter has some advantages such as low cost circuit configuration, simple control scheme and high efficiency. Its operating principle is described and to determine circuit parameters, some practical design considerations are discussed. The effectiveness of the proposed power converter is evaluated and compared with the hard switching PWM DC-DC converter from an experimental point of view and the comparative electromagnetic conduction and radiation noise characteristics of both DC-DC power converter circuits are also depicted.

• Health Policy and Management
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• v.25 no.3
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• pp.207-220
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• 2015

Background: The purpose of this exploratory study is to explain where, when and how the introduction of user fee system works in low and middle income countries using context, mechanism, and outcome configuration. Methods: Considering advanced research in realist review approach, we made a review process including those following 4 steps. They are identifying the review question, initial theory and mechanism, searching and selecting primary studies, and extracting, analyzing, and synthesizing relevant data. Results: User fee had a detrimental effect on medical utilization in low and middle income countries. Also previous and current interventions and community participation were critical context in user fee system. Those contexts were associated with intervention initiation and recognition and coping strategies. Such contexts and mechanisms were critical explanatory factors in medical utilization. Conclusion: User fee is a series of interventions that are fragile and dynamic. So the introduction of user fee system needs a comprehensive understanding of previous and new intervention, policy infrastructure, and other factors that can influence on medical utilization.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.176-192
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• 2014

The realization of Wireless Multimedia Sensor Networks (WMSNs) has been fostered by the availability of low cost and low power CMOS devices. However, the transmission of bulk video data requires adequate bandwidth, which cannot be promised by single path communication on an intrinsically low resourced sensor network. Moreover, the distortion or artifacts in the video data and the adherence to delay threshold adds to the challenge. In this paper, we propose a two stage Quality of Service (QoS) guaranteeing scheme called Prioritized Multipath WMSN (PMW) for transmitting H.264 encoded video. Multipath selection based on QoS metrics is done in the first stage, while the second stage further prioritizes the paths for sending H.264 encoded video frames on the best available path. PMW uses two composite metrics that are comprised of hop-count, path energy, BER, and end-to-end delay. A color-coded assisted network maintenance and failure recovery scheme has also been proposed using (a) smart greedy mode, (b) walking back mode, and (c) path switchover. Moreover, feedback controlled adaptive video encoding can smartly tune the encoding parameters based on the perceived video quality. Computer simulation using OPNET validates that the proposed scheme significantly outperforms the conventional approaches on human eye perception and delay.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.484-494
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• 2017

In industrial plants such as nuclear power plants, system operations are performed by embedded controllers orchestrated by Supervisory Control and Data Acquisition (SCADA) software. A targeted attack (also termed a control aware attack) on the controller/SCADA software can lead a control system to operate in an unsafe mode or sometimes to complete shutdown of the plant. Such malware attacks can result in tremendous cost to the organization for recovery, cleanup, and maintenance activity. SCADA systems in operational mode generate huge log files. These files are useful in analysis of the plant behavior and diagnostics during an ongoing attack. However, they are bulky and difficult for manual inspection. Data mining techniques such as least squares approximation and computational methods can be used in the analysis of logs and to take proactive actions when required. This paper explores methodologies and algorithms so as to develop an effective monitoring scheme against control aware cyber attacks. It also explains soft computation techniques such as the computational geometric method and least squares approximation that can be effective in monitor design. This paper provides insights into diagnostic monitoring of its effectiveness by attack simulations on a four-tank model and using computation techniques to diagnose it. Cyber security of instrumentation and control systems used in nuclear power plants is of paramount importance and hence could be a possible target of such applications.