• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.259-266
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• 2018

Purpose: This study is to investigate the pattern of discomfort, coping style and relief level of female workers. Methods: The subjects were 394 women who worked at three general hospitals located in S city and agreed to the purpose of this study. Data were collected April 20~30, 2010, and one-way ANOVA and Pearson's correlation were performed using descriptive statistics using SAS 9.2. Results: showed that discomfort during menstruation was significantly different from age, marital status, pregnancy experience, and birth experience. The average degree of discomfort during menstruation was $2.46{\pm}0.68$, which was the average of 5, and the pattern was pain, water accumulation and behavior change. The degree of mitigation according to coping strategies was the most effective at $3.55{\pm}0.58$, and the relationship between coping behavior and discomfort during menstruation was correlated only with avoidant coping. p = .001). Conclusion: In order to mitigate the inconvenience of menstruation, women should seek to cope with their own coping strategies rather than passive coping methods and suggest the development of an educational program that can relieve the discomfort during menstruation.

• Journal of IKEEE
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• v.18 no.2
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• pp.272-281
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• 2014

In electrical impedance tomography (EIT), modified Newton Raphson (mNR) method is widely used inverse algorithm for static image reconstruction due to its convergence speed and estimation accuracy. The unknown conductivity distribution is estimated iteratively by minimizing a cost functional such that the residual error namely the difference in measured and calculated voltages is reduced. Although, mNR method has good estimation performance, EIT inverse problem still suffers from ill-conditioned and ill-posedness nature. To mitigate the ill-posedness, generally, regularization methods are adopted. The inverse solution is highly dependent on the choice of regularization parameter. In most cases, the regularization parameter has a constant value and is chosen based on experience or trail and error approach. In situations, when the internal distribution changes or with high measurement noise, the solution does not get converged with the use of constant regularization parameter. Therefore, in this paper, in order to improve the image reconstruction performance, we propose a new scheme to determine the regularization parameter. The regularization parameter is computed based on residual error and updated every iteration. The proposed scheme is tested with numerical simulations and laboratory phantom experiments. The results show an improved reconstruction performance when using the proposed regularization scheme as compared to constant regularization scheme.

• Journal of Intelligence and Information Systems
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• v.19 no.4
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• pp.1-10
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• 2013

Personalization aims to provide customized contents to each user by using the user's personal preferences. In this sense, the core parts of personalization are regarded as recommendation technologies, which can recommend the proper contents or products to each user according to his/her preference. Prior studies have proposed novel recommendation technologies because they recognized the importance of recommender systems. Among several recommendation technologies, collaborative filtering (CF) has been actively studied and applied in real-world applications. The CF, however, often suffers sparsity or scalability problems. Prior research also recognized the importance of these two problems and therefore proposed many solutions. Many prior studies, however, suffered from problems, such as requiring additional time and cost for solving the limitations by utilizing additional information from other sources besides the existing user-item matrix. This study proposes a novel implicit rating approach for collaborative filtering in order to mitigate the sparsity problem as well as to enhance the performance of recommender systems. In this study, we propose the methods of reducing the sparsity problem through supplementing the user-item matrix based on the implicit rating approach, which measures the trust level among users via the existing user-item matrix. This study provides the preliminary experimental results for testing the usefulness of the proposed model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1927-1934
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• 2016

In this paper, we proposed a I-gate n-MOSFET (n-type Metal Oxide Semiconductors Field Effect Transistor) structure in order to mitigate a radiation-induced leakage current path in an isolation oxide interface of a silicon-based standard n-MOSFET. The proposed I-gate n-MOSFET structure was designed by using a layout modification technology in the standard 0.18um CMOS (Complementary Metal Oxide Semiconductor) process, this structure supplements the structural drawbacks of conventional radiation-tolerant electronic device using layout modification technology such as an ELT (Enclosed Layout Transistor) and a DGA (Dummy Gate-Assisted) n-MOSFET. Thus, in comparison with the conventional structures, it can ensure expandability of a circuit design in a semiconductor-chip fabrication. Also for verification of a radiation-tolerant characteristic, we carried out M&S (Modeling and Simulation) using TCAD 3D (Technology Computer Aided Design 3-dimension) tool. As a results, we had confirmed the radiation-tolerant characteristic of the I-gate n-MOSFET structure.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.270-274
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• 2017

Formic acid has been known as one of key sources of hydrogen. Among various monometallic catalysts, hydrogen can be efficiently produced on Pd catalyst. However, the catalytic activity of Pd is gradually reduced by the blocking of active sites by CO, which is formed from the unwanted indirect oxidation of formic acid. One of promising solutions to overcome such issue is the design of alloy catalyst by adding other metal into Pd since alloying effect (such as ligand and strain effect) can increase the chance to mitigate CO poisoning issue. In this study, we have investigated formic acid deposition on the bimetallic $Pd/Pd_3Fe$ core-shell nanocatalyst using DFT (density functional theory) calculation. In comparison to Pd catalyst, the activation energy of formic acid dehydrogenation is greatly reduced on $Pd/Pd_3Fe$ catalyst. In order to understand the importance of alloying effects in catalysis, we decoupled the strain effect from ligand effect. We found that both strain effect and ligand effect reduced the binding energy of HCOO by 0.03 eV and 0.29 eV, respectively, compared to the pure Pd case. Our DFT analysis of electronic structure suggested that such decrease of HCOO binding energy is related to the dramatic reduction of density of state near the fermi level.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1131-1138
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• 2004

In Hierarchical Mobile Ipv6 (HMIPv6) networks, the mobility anchor point (MAP) handles binding update (BU) procedures locally to reduce signaling overhead for mobility. However, as the number of mobile nodes (MNs) handled by the MAP increases, the MAP suffers from the overhead not only to handle signaling traffic but also to Process data tunneling traffic. Therefore, it is important to control the number of MNs serviced by the MAP, in order to mitigate the burden of the MAP. We propose an adaptive load control scheme, which consists of two sub-algorithms: threshold-based admission control algorithm and session-to-mobility ratio (SMR) based replacement algorithm. When the number of MNs at a MAP reaches to the full capacity, the MAP replaces an existing MN at the MAP, whose SMR is high, with an MN that just requests binding update. The replaced MN is redirected to its home agent. We analyze the proposed load control scheme using the .Markov chain model in terms of the new MN and the ongoing MN blocking probabilities. Numerical results indicate that the above probabilities are lowered significantly compared to the threshold-based admission control alone.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.64-76
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• 2006

Korea's overseas construction industry has been rather depressed by the weakened profitability as well as the sharp decrease of the market shares due to the lack of international competitiveness and the declined international market. There exist a lot of various risks in performing the overseas construction, and especially EPC projects, which entail complicated process from different parts, also require a sophisticated procurement and management skill. Subsequently, to survive in the competitive international market, we need to establish strategies to select potentially profitable projects at the initial stage of bidding process and to mitigate the high degree of risk exposure through contract negotiation and its adjustment. This research discusses the trend of environment in international construction markets. Then, it identifies the key factors that affect the profitability significantly through the structured surveys from 59 actual overseas projects, and it analyzes the key factors by using statistical methods. This research provides the profitability evaluation bases, with which overseas construction participants can forecast and analyze the risk more systematically, by eliciting profit-influencing factors using the result of statistical analysis, literature review and structuring their cause-and-effect relationships. The profitability casual hierarchy structure describes the profitability factors' hierarchy in details and their interrelationships. It also enables us to find out critical factors directly related to profitability aggravation through a qualitative and quantitative analysis. Ultimately, with this hierarchy structure as the base, the research will suggest how to develop the quantitative profitability forecasting model.

• Korean Journal of Construction Engineering and Management
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• v.18 no.3
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• pp.105-116
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• 2017

In recent years, large Korean construction companies have suffered serious losses in their overseas business. Many practitioners and researchers have analyzed causes of cost overrun in these projects. However, these arguments have not been empirically verified based on acutal project cases. This study investigated cost overrun rate, contingency, allowance, predicted risk before bidding, and actual and residual risk after award in the 67 international infrastructure projects conducted by 13 large construction companies. The causes of cost overruns are derived as follows. First, they identified the possibility of cost overrun to some extent before the bidding, but did not reflect the enough risk money to bid price. In particular, this behavior was more severe in badly cost-overrun projects. Second, the causes of cost overrun were more influenced by external environmental risk than internal capability risk. However, the internal risk in badly cost-overrun projects was relatively high compared to cost-underrun projects. Third, badly cost-overrun projects failed to mitigate risk. However, cost underrun projects were affected more by low exterior risk conditions than by well mitigated risk. This study provides more informed knowledge in controlling project costs in international infrastructure projects.

• KDI Journal of Economic Policy
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• v.30 no.2
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• pp.61-97
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• 2008

This paper aims at analyzing the practice of job rotation in the Korean government and putting forward policy suggestions. The Korean government is often accused of low capacity and weak competitiveness, which mainly result from the low expertise of public officials. Considering the high quality of human resources flowing into the public sector in Korea, solutions should be found from the structure of the system. This paper regards frequent position changes due to excessive job rotation as a key factor undermining the accumulation of expertise and conducts in-depth analyses. The current practice of frequent rotation shows that the average tenure period of government officials at director level and above is only about one year, far shorter than those in major developed countries, which causes many problems such as low efficiency, lack of accountability and policy consistency, and low opportunity for accumulating expertise. Simple models are set up to analyze job rotation and other alternative personnel management systems. Analyses find that it would be desirable to have each individual experience various positions during the initial rotation period to find his/her own aptitude, and then accumulate expertise by settling in at a certain specialized field for a prolonged period of time based on the revealed aptitude in mid and high positions. This turns out to be in line with the structure of the Career Development Program which is being introduced. The model-based analysis of this paper distinguishes this study from preceding ones conducted in the traditional framework of personnel management study. Practical measures to mitigate the problems of frequent job rotation include rotating within the area of specialty, narrowing the scope of transfer, and reinforcing the minimum tenure period. However, since the current frequent rotation is fundamentally attributable to the rank system based on seniority, the present civil service classification system needs to be converted into a position classification system in the long run.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.63-76
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• 2004

This paper presents LRB-based hybrid base isolation systems employing additional active/semiactive control devices for mitigating earthquake-induced vibration of a cable-stayed 29 bridge. Hybrid base isolation systems could improve the control performance compared with the passive type-base isolation system such as LRB-installed bridge system due to multiple control devices are operating. In this paper, the additional response reduction by the two typical additional control devices, such as active type hydraulic actuators controlled by LQG algorithm and semiactive-type magnetorheological dampers controlled by clipped-optimal algorithm, have been evaluated bypreliminarily investigating the slightly modified version of the ASCE phase I benchmark cable-stayed bridge problem (i.e., the installation of LRBs to the nominal cable-stayed bridge model of the problem). It shows from the numerical simulation results that all the LRB based hybrid seismic isolation systems considered are quite effective to mitigate the structural responses. In addition, the numerical results demonstrate that the LRB based hybrid seismic isolation systems employing MR dampers have the robustness to some degree of the stiffness uncertainty of in the structure, whereas the hybrid system employing hydraulic actuators does not. Therefore, the feasibility of the hybrid base isolation systems employing semiactive additional control devices could be more appropriate in realfor full-scale civil infrastructure applications is clearly verified due to their efficacy and robustness.