• KIISE Transactions on Computing Practices
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• v.21 no.6
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• pp.393-402
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• 2015

Human resources are one of the most essential elements of an organization. In particular, the more closed a group is, the higher the value each member has. Previous studies have focused on personal attributes of individual, such as medical history, and have depended upon self-diagnosis to manage structures. However, this method has weak points, such as the timeconsuming process required, the potential for concealment, and non-disclosure of participants' mental states, as this method depends on self-diagnosis through extensive questionnaires or interviews, which is solved in an interactive way. It also suffers from another problem in that relations among people are difficult to express. In this paper, we propose a multi-faced diagnosis model based on social network analysis which overcomes former weaknesses. Our approach has the following steps : First, we reveal the states of those in a social network through 9 questions. Next, we diagnose the social network to find out specific individuals such as victims or leaders using the proposed algorithm. Experimental results demonstrated our model achieved 0.62 precision rate and identified specific people who are not revealed by the existing methods.

• Ocean Systems Engineering
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• v.6 no.3
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• pp.245-264
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• 2016

The iterative boundary element method (IBEM) developed originally before for cavitating two-dimensional (2-D) and three-dimensional (3-D) hydrofoils moving under free surface is modified and applied to the case of 2-D (two-dimensional) airfoils and 3-D (three-dimensional) wings over water. The calculation of the steady-state flow characteristics of an inviscid, incompressible fluid past 2-D airfoils and 3-D wings above free water surface is of practical importance for air-assisted marine vehicles such as some racing boats including catamarans with hydrofoils and WIG (Wing-In-Ground) effect crafts. In the present paper, the effects of free surface both on 2-D airfoils and 3-D wings moving steadily over free water surface are investigated in detail. The iterative numerical method (IBEM) based on the Green's theorem allows separating the airfoil or wing problems and the free surface problem. Both the 2-D airfoil surface (or 3-D wing surface) and the free surface are modeled with constant strength dipole and constant strength source panels. While the kinematic boundary condition is applied on the airfoil surface or on the wing surface, the linearized kinematic-dynamic combined condition is applied on the free surface. The source strengths on the free surface are expressed in terms of perturbation potential by applying the linearized free surface conditions. No radiation condition is enforced for downstream boundary in 2-D airfoil and 3-D wing cases and transverse boundaries in only 3-D wing case. The method is first applied to 2-D NACA0004 airfoil with angle of attack of four degrees to validate the method. The effects of height of 2-D airfoil from free surface and Froude number on lift and drag coefficients are investigated. The method is also applied to NACA0015 airfoil for another validation with experiments in case of ground effect. The lift coefficient with different clearance values are compared with those of experiments. The numerical method is then applied to NACA0012 airfoil with the angle of attack of five degrees and the effects of Froude number and clearance on the lift and drag coefficients are discussed. The method is lastly applied to a rectangular 3-D wing and the effects of Froude number on wing performance have been investigated. The numerical results for wing moving under free surface have also been compared with those of the same wing moving above free surface. It has been found that the free surface can affect the wing performance significantly.

• Korean Journal of Psychosomatic Medicine
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• v.9 no.2
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• pp.111-132
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• 2001

Depression in the medically ill is a common clinical problem that primary physicians and psychiatric consultants encounter. Treatment of such patients begins with a careful evaluation of the patient's medical and psychiatric conditions. The assessment of depression in the medical patients requires a multidimensional approach. Psychological instruments are also used as a method of assessment in these patients. First of all, what the therapists have to do is to find and remove organic causes. Psychosoical treatment includes dealing with the patient's resistance and despondency relevant to physical diseases. For biological treatment, it is important to select appropriate antidepressants. Therapists should be familiar with the side effects of the antidepressants as well as the patient's primary depressive symptoms, pharmacokinetics and pharmacodynamics of the available agents. In addition, special attention should be paid to the potential for drug-illness and drug-drug interactions. Tricyclic antidepressants can be still effectively used for patients with pain disorder, although a variety of new antidepressants such as selective serotonin reuptake inhibitors (SSRI), bupropion and venlafaxine could have more benefits in depression of the medically ill. However, electroconvulsive therapy can be recommended for refractory cases of depression in patients with medical illness.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.58
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• pp.215-236
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• 2013

It is quite true that the more Korean contractors receive overseas contracts, the more they need guarantees. The top market for them is the Middle East countries, consisting of more than the half of the total amount awarded last year and the trend is increasing as well. The problem, however, is that employers in these countries are reluctant to use international rules for guarantee such as URDG or ISP98 and easily make unfair callings. However, Korean contractors(applicants), especially small and medium sized enterprises(SMEs) tend to hurriedly enter a contract without looking into its contents as well as guarantees. They do not realize the importance of the guarantees until they receive callings from the employers(beneficiaries). Being independent from the underlying contracts, guarantee is the equivalent to cash in that it usually does not require any proof of demand when calling and the guarantor should make a payment within usually 5 business days after the request. It is often observed these days that several Korean SMEs go bankrupt due to liquidity risks after receiving unfair callings from employers in the Middle East countries. In retrospect, some cases could be obviated if contractors were a little more careful in checking the contents of a guarantee at the time of concluding a contract. For example, there is one case where the underlying contract includes a reduction clause in the Advance Payment bond and the guarantee does not have that clause. In the end, the Korean contractor had to take the whole burden of the bond amount though it had finished 81% of the project. Nobody could argue that contractors should take a full responsibility if they fail in their obligations. However, the employer's wrongful callings need to be prevented in the first place, if possible. As there shouldn't be a case where one party is at a disadvantage against the other like the case mentioned above, useful insight is being sought to minimize unfair calling risks for the benefit of the applicant. First, the applicant should carefully look into every detail of the potential guarantee before signing a contract, heeding especially that there is a reduction clause in the AP bond. Second, the governing principles for guarantee should be the ones that are internally used such as URDG758 that is objective in terms of callings given that, for example, it specifies that the requirement for a supporting statement when making a demand is a default rule. It is also recommended that the form of guarantees be the standard demand guarantee. Third, parties involved in issuing guarantees are advised to understand international rules for guarantee like URDG758 and ISP98 and to play a key role in guiding SME contractors in Korea so that they can protect themselves from possible wrongful callings, particularly from employers in the Middle East countries. I hope this study would give a wake-up call for Korean SMEs wishing to do business in the Middle East countries and remind them of the importance of guarantee itself and its governing principles.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.2
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• pp.53-60
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• 2015

Newly, nutrients recovery by bioconversion in the swine waste which caused serious problems due to its high organic fraction and content of nutrients such as phosphorus and nitrogen is viewed as a considerable approach since it produces valuable product as well as recycling of resources. Consequently, it is necessary to find new methods to treat swine waste. One possible solution to this problem is to use this potential pollutant as a growth substrate for economically valuable products. The study for the fundamental improvement of bioconversion efficiency by finding optimum growth conditions using statistical models and biotechnology was performed. A novel approach to utilize swine waste by cultivating mycelia of the mushroom Phellinus linteus are described. A central composite face-centered design (CCF) for the experiments was used to develop empirical model providing a quantitative interpretation of the relationships among the three variables, which were substrate concentration, pH, and temperature. The maximal radial extension rate (2.78mm/d) of P.linteus was determined under the condition of 5.0 g COD/L, pH 5.0, and temperature $29.7^{\circ}C$. The results of this study suggest that swine waste could be utilized as a growth substrate for the cultivation of mushroom mycelia enhancing an efficiency of utilizing this by-product of the livestock industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.545-552
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• 2017

Ground subsidence can result in the formation of sinkholes, potholes, settlement of structures, and road subsidence. Road subsidence is described as the sudden collapse of the road surface into subsurface cavities caused by the loss of bearing capacity in the ground, such as the dissolution of limestone by fluid flow in the surface causing the formation of voids leading to subsidence at the surface. Road subsidence occurs about 665 times annually, and this incidence has been increasing until 2013. Damaged underground facilities, management negligence, and lowering of the ground water table have been the causes of road subsidence in Seoul. Seoul metropolitan government announced special management counter plans to relieve the anxieties and make the roads safe for passing. Construction sites, such as excavation works, need to be managed properly because they have strong potential to induce road subsidence. The aim of this study was to identify the main causes of road subsidence and suggest management plans. First, life cycle cost analysis revealed the daytime construction to be more appropriate than nighttime. In addition, by analyzing the limitations of using sand as a backfill material, it is proposed to use a flowable backfill material instead of sand. Finally, to reduce the blind spots, which is a problem in surveying the road pavement conditions of local governments, the road to be managed is divided into several zones, and a specialized agency is selected for each zone and a method of surveying the blind spots through collaboration is suggested.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.475-486
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• 2009

Regular activity program is needed for managing chronic disease and obesity and preventing falls as a nursing intervention. It seems that serious game will be very important for older people to keep them active with fun to improve their health. This study was conducted to explore the correlations between health problems and computer game needs in the elderly. This was a cross-sectional study. A questionnaire was developed and administered to a convenience sample of adults who are older than 55 years, recruited from several places through trained research assistants and research center that has online pools in Korea. 778 subjects (mean age: $61.4\;{\pm}\;5.6$) were participated in this study. The majority of subjects was male (68.6%). We found that there was higher needs for exercise or serious game in the group of ma1e(55.4%), below undergraduate(66.2%), under two family members(32.5%), over 350,000 won of pocket money/month (40.1%), mild depressive symptom (51.7%), and online responser(68%). Especially, they wanted to overcome physical limitations through games. Higher education, more experiences and skills of using computer/internet was statistically and positively significant to the needs for exercise or serious game. In conclusion, there exists a potential market within this demographic group for the use of serious games. Thus, we need to develop senior games in Korean to improve quality of life and health promotion.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.120-125
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• 2015

With rapid urbanization, the volume of traffic in urban area has been significantly increased. This in turn led to problem which can be described as Road Traffic Noise. Currently, to alleviate the road traffic noise damage, a demand for installation of soundproofing walls is rising. Among different shapes of soundproof walls being installed, the reflection-type acoustical insulation panel is highly drawing attentions of residents due to the fact that it does not obstruct their field of vision in contrast with the opaque acoustical insulation panel. On the other hand, improving the soundproofing wall of the reflection-type acoustical insulation barrier panel needs to be focused on since it has a possibility to cause a secondary damage by reflected sounds. Therefore, in this research, study has been carried out to improve the forms in order to minimize travelling of reflected sounds through changing the frontal surface shape and geometrical shape of the reflection-type soundproofing panel. A result from comparison between the normal reflection-type soundproofing panel and the improved soundproofing panel, with reduction effects in the noise reflection, showed that the curved type of soundproofing panel has an impact on reducing the noise up to 1.5 dB. Furthermore, from the research conducted, it appears that the increase and decrease in the reflected sounds can be changeable depending on various design factors. Thus, it turns out that the study shows a potential possibility to develop a reduction technology of the reflected sounds pertaining to overall condition on the soundproofing walls.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1060-1068
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• 2007

Perchlorate contamination in aquatic system is a growing concern due to the human health and ecological risks associated with perchlorate exposure. In spite of potential risks associated with perchlorate, drinking water standard has not been established worldwide. Recently, US EPA has issued new protective guidance for cleaning up perchlorate contamination with a preliminary clean-up goal of 24.5 ppb. In Korea, the drinking water standard and discharge standard for perchlorate has not been established yet and little information is available to address perchlorate problems. Perchlorate treatment technologies include ion exchange, microbial reactor, carbon adsorption, composting, in situ bioremediation, permeable reactive barrier, phytoremediation, and membrane technology. The process description, capability, and advantage/disadvantages of each technology were described in detail in this review. One of recent trends in perchlorate treatment is the combination of available treatment options such as combined microbial reduction and permeable reactive burier. In this review, we provided a brief perspective on perchlorate treatment technology and to identify an efficient and cost-effective approach to manage perchlorate problem.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.604-609
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• 2020

The purpose of this study is to check the priority control status of the current operation process alarm by comparing the priority of the alarm set up in PV high trip point, which is being installed and operated in the domestic petrochemical industry, with the criteria presented in ISA 18.2 International Standard or EEMUA 191 Guidelines. In the event of a process problem, excessively set high alarm is provided to the driver in a short period of time, making it difficult to identify the alarm that needs to be handled first. As a result, it is likely that the operator will not be able to carry out appropriate actions within the specified time frame, and many cases have been reported leading to unexpected process shutdowns or process accidents. Therefore, this study aims to introduce international standards related to alarm management and identify the level of alarm control used at the domestic petrochemical industry site to inform potential risks that may occur in the petrochemical process of the national industrial complex in the future and suggest ways to reduce risk factors. This paper was submitted to Professor Lee Inbeom's retirement anniversary issue.