• 조명전기설비학회논문지
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• 제16권5호
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• pp.38-44
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• 2002

본 논문에서는 배전선의 전압관리를 위한 계측시스템의 개발에 관하여 제안한다. 배전선 전압특성 및 측정상의 문제점이 분석되고, 전압관리를 위한 계측기의 기능에 대하여 제안한다. 노이즈 특성이 좋은 이중기울기(dual-slope) 방식의 A/D 컨버터를 적용하여 전압측정을 하는 알고리즘과 배전선 전압관리계기의 개발에 관하여 제안한다. IEEE 1159기준 분석에 따른 배전선의 정전 및 복귀 와 규정전압 초과 빈도 수 같은 전압변동 특성 등이 데이터베이스 제안에 의하여 분석된다. 실험을 통하여 그 편리성이 증명된다.

• Fisheries and Aquatic Sciences
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• 제18권1호
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• pp.7-11
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• 2015

The influence of spice (cinnamon, allspice, black pepper)-oil extract on canned seafood quality was studied. During the processing of canned seafood, the substitution of spice-oil extract for vegetable oil (refined sunflower, corn, soybean and olive oil) resulted in a decrease in the heat resistance of spore microorganisms, making it possible to reduce the duration of sterilization for canned food to 5-10 min at $115^{\circ}C$. This reduction in the sterilization duration of canned seafood with spice-oil extract inhibited residual microflora in the product, thus reducing the deleterious effect of heating on the main food compounds while preserving protein digestibility.

• KDI Journal of Economic Policy
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• 제40권3호
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• pp.1-44
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• 2018

This paper studies the macroeconomic effects of an enhancement in unemployment benefits in Korea. In particular, I quantify the welfare effect of two specific policy chances which have been mainly discussed among policymakers in recent years: increasing wage replacement rates by 10%p and extending maximum benefit durations by one month. To this end, I build and calibrate an overlapping generation model which reflects the heterogeneity of the unemployed and the specificity of the unemployment insurance (UI) system in Korea. The quantitative analysis conducted here shows that extending maximum benefit durations by one month improves social welfare, whereas increasing wage replacement rates by 10%p deteriorates social welfare. Extending maximum benefit durations is applied to potentially all the UI recipients, including unemployed workers whose wage before job loss is relatively low and whose marginal utility is relatively high. However, increasing wage replacement rates is applied to only a small number of UI recipients whose wage before job loss is relatively high, while the increase in the UI premium is passed onto all of the employed. This study suggests that given the current UI system and economic environment in Korea, it is more desirable to extend maximum benefit durations rather than to increase wage replacement rates in terms of social welfare.

• 한국전문물리치료학회지
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• 제16권1호
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• pp.34-41
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• 2009

The purpose of this study is to compare the outcomes of manual stretching treatment with those of motor development and positioning physical therapy (MDPPT) for congenital muscular torticollis (CMT). This study was designed to be randomized controlled trials and to evaluate the outcomes of 43 consecutive patients with CMT who were first seen when they were average 26 days old. Before treatments, the patients were unintentionallv classified into two clinical groups along with the treatment methods. Among the 43 patients, 22 were classified to the manual stretching group and 21 to the MDPPT group. By means of independent t-test on the result. the duration of treatment according to methods was not significantly different in two groups (p>.05). The duration of treatment in accordance with head tilt level was not significantly different in two groups (p>.05). There was change of mass diameter, between at the beginning day of treatment and after treatment in manual stretching group with a strong positive linear correlation (p=.000, r=.734), but slightly positive linear correlation in MDPPT group. The result of this study indicates that two therapeutic methods make little difference in effectiveness.

• 한국군사과학기술학회지
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• 제21권1호
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• pp.115-123
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• 2018

In this paper, we consider the applicability of time-hopping(TH) systems for anti-jamming(AJ) communication. We first briefly summarize fundamentals of TH systems and several common jamming scenarios that have been considered in the literature. We then analyze the AJ performance of TH systems under those common jamming environments. From our simulation results, we reveal that among narrow band, partial band, broadband, and sweep jamming, partial band and sweep jamming are the best ones from jammer perspective. For the partial band jamming case, we show that the most effective bandwidth ratio and location are 50 % and 2.5-3.5 Ghz, respectively. For the sweep jamming case, we illustrate that the AJ performance of the TH system is enhanced when the sweep duration approaches to the bit duration. In addition, we pointed out that the most efficient jamming bandwidth ratio is 1/2. Finally, our results show that the TH-BPSK system greatly outperforms the TH-PPM counterpart.

• 대한기계학회논문집A
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• 제20권12호
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• pp.3767-3781
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• 1996

Generally, dynamic loads are applied to real structures. Since the analysis with the dynamic load is extremely difficult, static loads are utilized by proper conversions of the dynamic loads. The dynamic loads are usually converted ot static loads by safety foactors of experiences. However, it may increase weight and decrease reliability. In this study, a method is proposed for the conversion process. An equivalent static load is calculated ot generate a same maximum displacement. The method is verified through numerical tests on a spring-mass systems of one and multi degrees-of freedom. It has been found that the duration time of the loads and the natural frequencies of the structures are critical in the conversion process. A road arem is a self-propelled howizer is selected for the application of the proposed method. The shape of the road arm is optimized under the converted static loads.

• 한국산업보건학회지
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• 제28권3호
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• pp.267-272
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• 2018

Objective: This study aimed to test the accuracy of self-reported information used in indirect estimation of pesticide exposure. Methods: To do so, self-reported values on the duration of pesticide application per day were compared with observed values. The number of days of pesticide application per year as recorded in self-administered logs was compared with recalled values. Results: It was found that participants underestimated the duration and frequency of actual pesticide use. High correlations were found between self-reported values and observed values, as well as between recalled values and recorded values. Conclusions: The reason might be that farmers unconsciously under-recall the application of pesticide since many customers prefer eco-friendly agricultural products. Farmers thought the task of applying pesticides to be essential, and this may explain why the participants in this study tended to accurately recall their pesticide-related work.

• 대한기관식도과학회지
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• 제4권1호
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• pp.85-90
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• 1998

The role of the ECP(Eosinophilic cationic protein) is still unknown in the allergic rhinitis. In bronchial asthma, ECP can induce the exposure of the neuropeptidergic nerve to environments destroying the bronchial mucosa, aggravating the bronchial hypersensitivity and delay the mucociliary clearance. In the clinical aspect, we can (md that patients with perennial allergic rhinitis sometimes have sinusitis. The purpose of this article is to evaluate whether mucosal damage by ECP can play a role to develop the sinusitis by delaying the mucociliary clearance, and relationship between long symptom duration of allergic rhinitis and mucociliary clearance. In 32 perennial allergic rhinitis patients, we elucidated there is correlation among ECP presence, mucociliary clearance, sinusitis, and symptom durations. The obtained results were as follows : 1. ECP appeared in all mucosa of each specimen. 2. Mean mucociliary clearance time is 6 mins. 12 sec. in allergic patients with sinusitis, 6 mins. 36 sec in allergic patients without sinusitis. 3. n out of 32 cases have mucosal destruction. 4. Symptom duration is not correlated with the development of sinusitis. This study suggests that ECP may destroy the mucosa in allergic rhinitis and the mucociliary clearance of allergic rhinitis is not related to sinusitis and symptom dotation. Therefore development of sinusitis in allergic rhinitis seems not to be caused by delaying of mucociliary clearance due to mucosal destruction, but by some other factors.

• Imaging Science in Dentistry
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• 제47권1호
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• pp.45-50
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• 2017

Purpose: The aim of this study was to investigate the incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ) after tooth extraction in patients with osteoporosis on oral bisphosphonates in Korea and to evaluate local factors affecting the development of BRONJ. Materials and Methods: The clinical records of 320 patients who underwent dental extraction while receiving oral bisphosphonates were reviewed. All patients had a healing period of more than 6 months following the extractions. Each patient's clinical record was used to assess the incidence of BRONJ; if BRONJ occurred, a further radiographic investigation was carried out to obtain a more definitive diagnosis. Various local factors including age, gender, extraction site, drug type, duration of administration, and C-terminal telopeptide (CTx) level were retrieved from the patients' clinical records for evaluating their effect on the incidence of BRONJ. Results: Among the 320 osteoporotic patients who underwent tooth extraction, 11 developed BRONJ, reflecting an incidence rate of 3.44%. Out of the local factors that may affect the incidence of BRONJ, gender, drug type, and CTx level showed no statistically significant effects, while statistically significant associations were found for age, extraction site, and duration of administration. The incidence of BRONJ increased with age, was greater in the mandible than the maxilla, and was associated with a duration of administration of more than 3 years. Conclusion: Tooth extraction in patients on oral bisphosphonates requires careful consideration of their age, the extraction site, and the duration of administration, and close postoperative follow-up should be carried out to facilitate effective early management.

• 한국세라믹학회지
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• 제31권9호
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• pp.1076-1086
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• 1994

This study covers synthetic effect of the various hydrothermal treatments on formation of artificially made kaolinite mineral. The hydrothermal treatment includes the temperature treatment with time duration, addition of seeds, particle size of the starting material used, pH variation and the different types of organic acids. A colloidal silica and alumina sol which are commercially available are used for this study. A colloidal silica and alumina sol are mixed by the atomic ratio of Al/Si = 1, based on the theoretical kaolinite composition and calcined at $600^{\circ}C$ for 8 hours duration. It was found that the kaolinitic clay mineral was well developed; thereby, the different patterns of crystalline mineral are appeared. Spherical type as a crystal form was distinctively formed at the temperature of 20$0^{\circ}C$ to 25$0^{\circ}C$ with short duration time, while platy type as a crystal was highly yielded at 300~35$0^{\circ}C$. Moreover, by adding more than 20 wt% of seed as the natural kaolinitic clay to the starting material is widely distributed and developed when 2 ${\mu}{\textrm}{m}$ or less particle size of the starting material is used; also, when they are heat-treated at the temperature of 25$0^{\circ}C$ with 5 hours duration. With respect of the effect of pH variation on formation of the synthetic kaolinite minerals, the crystalline minerals are highly yielded at less than pH 2 and gradually diminished at more than pH9. Regarding to the effect of different acids on development of the kaolinite mineral, the organic acids with high chelating capacity produces good formation of crystalline minerals; whereas, amine radical-(NH2) is not an effective agent to generate the crystalline minerals.