• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.195-201
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• 1989

Voltage collapse is a serious concern to the electirc utility industry. It is common to associate steady-state stability with the ability of the transmission system to transport real power and to associate voltage collapse with the inability to provide reactive power at the necessary locations within the system. An algorithm to directly calculate the critical point of system voltage collapse was presented by the authors. The method (based on the ordinary power flow equations and explicit requirement of singularity of the Jacobian matrix) is basically one degree of freedom with proper load distribution factors. This paper suggests a modified algorithm to increase the degree of freedom, introducing the nonlinear programming technique. The objective function is a distance measure between the present operating point and the closest voltage collapse point. Knowledge of the distance and the most vulnarable bus from the voltage collapse point of view may be used as a useful index for the secure system operation.

• Communications for Statistical Applications and Methods
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• 제10권1호
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• pp.89-99
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• 2003

The primary purpose of this paper is to estimate the wealth effect. We establish a linear relationships between household consumption, labor income, and stock price index. Each variable is nonstationary. And so, it contains a unit root. However, as the result of the test about cointegrating relations, the variables are cointegrated which implies the error term is stationary. The cointegrating parameter that the marginal propensity to consume out of stock price is 0.08%. The result of estimation shows the error correction is -0.62 and the significant level is also high. The error correction term indicates a rather rapid adjustment to deviations from the long run equilibrium relations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.227-229
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• 2004

In a new competitive market environment, it is very important to determines how much power can be transferred through the network. It's known as Available Transfer Capability(ATC). This paper presents a technique to evaluate Reliability Assesment and the Available Transfer Capability of Haenam-Cheju HVDC transmission system using Well-being Method which is based on the probabilistic method. The system Well-being is categorized in terms of the system Healthy and Marginal in addition to the conventional Risk index. Haenam-Cheju HVDC system has been studied for the optimal ATC based in well-being categories.

• Geomechanics and Engineering
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• 제28권1호
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• pp.35-48
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• 2022

The effect of discrete polypropylene fibre reinforcement on shear strength parameters, tensile properties and isotropic index of stabilized compacted residual subgrade was investigated. Composites of compacted subgrade were developed from polypropylene fibre dosage of 0%, 1%, 2.5% and 4% and 3% cement binder. Saturated compacted soil benefited from incremental fibre dosage, the mobilized friction coefficient increased to a maximum at 2.5% fibre dosage from 0.41 to 0.58 and the contribution due to further increase in fibre dosage was marginal. Binder stabilization increased the degree of isotropy for unreinforced soil at lower fibre dosage of 1% and then decreased with higher fibre dosage. Saturation of 3% binder stabilized soil decreased the soil friction angle and the degree of isotropy for both unstabilized and binder stabilized soil increased with fibre dosage. The maximum tensile stress of 3% binder stabilized fibre reinforced residual soil was 3-fold that of 3% binder stabilized unreinforced soil. The difference in computed and measured maximum tensile and tangential stress decreased with increase in fibre dosage and degree of stabilization and polypropylene fibre reinforced soil met local and international criteria for road construction subgrade.

• Nutrition Research and Practice
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• 제8권6호
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• pp.688-694
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• 2014

BACKGROUND/OBJECTIVES: Recent research regarding vitamin $B_6$ status including biochemical index is limited. Thus, this study estimated intakes and major food sources of vitamin $B_6$; determined plasma pyridoxal 5'-phosphate (PLP); and assessed vitamin $B_6$ status of Korean adults. MATERIALS/METHODS: Three consecutive 24-h diet recalls and fasting blood samples were collected from healthy 20- to 64-year-old adults (n = 254) living in the Seoul metropolitan area, cities of Kwangju and Gumi, Korea. Vitamin $B_6$ intake and plasma PLP were analyzed by gender and by vitamin $B_6$ supplementation. Pearson's correlation coefficient was used to determine associations of vitamin $B_6$ intake and plasma PLP. RESULTS: The mean dietary and total (dietary plus supplemental) vitamin $B_6$ intake was $1.94{\pm}0.64$ and $2.41{\pm}1.45mg/day$, respectively. Median (50th percentile) dietary intake of men and women was 2.062 and 1.706 mg/day. Foods from plant sources provided 70.61% of dietary vitamin $B_6$ intake. Only 6.3% of subjects consumed total vitamin $B_6$ less than Estimated Average Requirements. Plasma PLP concentration of all subjects was $40.03{\pm}23.71nmol/L$. The concentration of users of vitamin $B_6$ supplements was significantly higher than that of nonusers (P < 0.001). Approximately 16% of Korean adults had PLP levels < 20 nmol/L, indicating a biochemical deficiency of vitamin $B_6$, while 19.7% had marginal vitamin $B_6$ status. Plasma PLP concentration showed positive correlation with total vitamin $B_6$ intake (r = 0.40984, P < 0.0001). CONCLUSIONS: In this study, vitamin $B_6$ intake of Korean adults was generally adequate. However, one-third of subjects had vitamin $B_6$ deficiency or marginal status. Therefore, in some adults in Korea, consumption of vitamin $B_6$-rich food sources should be encouraged.

• 노동경제논집
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• 제39권2호
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• pp.113-139
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• 2016

본 연구는 한국프로야구리그(KBO)에서 활동하는 개별선수의 승리에 대한 기여도, 즉 생산성을 추정하는 모형의 구축을 목적으로 한다. 기존의 지표인 대체선수대비승수(WAR)의 단점인 계산방법의 복잡성을 해결하기 위하여 KBO 공식 홈페이지에서 제공하는 기록만을 이용한 계량모형을 구축함으로써 새로운 시즌의 기록만 대입하면 생산성을 생성할 수 있게 하였다. 또한, Scully(1974)와 Krautman(1999) 등 미국 메이저리그 선수의 가치추정모형이 소수의 기록에만 의존하였던 점을 개선하여 KBO가 발표하는 61개 기록을 모두 사용하여 현실에 적용할 수 있는 모형을 구축하였다. 2002-14년 팀기록의 패널 자료를 이용하여 득점 및 실점방정식을 추정하여 회귀분석에 기초한 대체선수대비승수를 추산하였다. 추정 결과, WAR과 상관계수가 타자는 0.869, 투수는 0.882로 나타나 두 지표가 비교적 유사한 것으로 나타났다. 추정 결과를 근거로 2014년 시즌 후 FA선수들의 계약 내용을 평가하면 비교적 생산성 추정치와 계약액수의 상관관계가 높아서 구단이 FA계약에서 합리적인 판단을 하고 있는 것으로 나타났다.

• 한국수산과학회지
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• 제44권6호
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• pp.695-700
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• 2011

Age, growth, and maturity of Trichiurus lepturus were estimated based on right-handed sagittal otoliths belonging to 1,031 fish collected from January to December 2007 in the East China Sea. The outer margins of the otolith were examined and showed that an opaque zone was formed once per year. Marginal increments in otoliths formed as annual rings between June and August, at the beginning of the spawning season. Fish growth was expressed by the von Bertalanffy growth equation, as follows: $L_t=494.0$ ($1-e^{-0.2453(t+-0.4822)}$) for females and $L_t=330.4$ ($1-e^{-0.4292(t+0.7513)}$) for males, where $L_t$ is the total length in mm and t is age in years. The growth rates of males and females were significantly different (P<0.05).The age composition ranged mostly between ages 2 and 4, and the oldest individuals were 4 years old in males and 6 years old in females. Finally, the age composition of largehead hairtail was compared with data from the 1970s and is discussed in the context of environmental changes.

• BLOOD RESEARCH
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• 제53권4호
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• pp.307-313
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• 2018

Background Primary ocular adnexal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (POML) is the most common subtype of lymphoma involving the eyes in Thailand. We sought to assess the characteristics and treatment outcomes of patients with POML in Thailand. Methods We retrospectively reviewed patient data and included patients diagnosed with POML between January 2004 and December 2016 at Chiang Mai University Hospital and King Chulalongkorn Memorial Hospital, Thailand. We collected and analyzed patients' clinical characteristics and treatment outcomes. Results Among 146 patients with lymphoma involving the eyes, 121 (82%) were diagnosed with POML. Sixty-four (52.9%) were women with median age 58 (range, 22-86) years. The most common presenting symptom was orbital mass (71.1%). Common sites of origin were the orbit (46.3%) and lacrimal gland (34.7%). At presentation, 22.3% of patients had bilateral eye involvement. About half of patients had stage I disease (N=59, 56.2%) and 20% had stage IV. Most patients (73.3%) had a low-risk International Prognostic Index. Radiotherapy was the main treatment for patients with limited-stage disease (66.7% in stage I and 56.5% in stage II). The overall response rate was 100% with complete response rates 80%, 77.3%, and 64.7% for stages I, II, and IV, respectively. Five-year progression-free survival (PFS) and overall survival were 66.1% and 94.0%, respectively. For patients with limited-stage disease, radiotherapy significantly improved PFS compared with treatment not involving radiotherapy (5-year PFS 89.9% vs. 37.3%, P=0.01). Conclusion We revealed that POML has good response to treatment, especially radiotherapy, with excellent long-term outcome.

• Journal of Periodontal and Implant Science
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• 제45권5호
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• pp.169-177
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• 2015

Purpose: Despite the high success rates of endosseous dental implants, their placement is restricted according to the height and volume of bone available. The use of short or mini dental implants could be one way to overcome this limitation. Thus, this study aimed to compare standard, short, and mini dental implants with regard to associated clinical parameters and peri-implant crevicular fluid (PICF) levels of cathepsin-K (CTSK), RANK ligand (RANKL), and osteoprotegerin (OPG), after prosthodontic loading. Methods: A total of 78 non-submerged implants (Euroteknika, $Aesthetica^{+2}$, Sallanches, France) were installed in 30 subjects (13 male, 17 female; range, 26-62 years) who visited the clinic of the Periodontology Department, Faculty of Dentistry, Selcuk University. Sampling and measurements were performed on the loading date (baseline) and 2, 14, and 90 days after loading. Assessment of the peri-implant status for the implant sites was performed using the pocket probing depth (PPD), modified plaque index, modified gingival index, modified sulcular bleeding index, and radiographic signs of bone loss. PICF samples collected from each implant were evaluated for CTSK, RANKL, and OPG levels using the ELISA method. Keratinized tissue and marginal bone loss (MBL) were also noted. Results: Clinical parameters statistically significantly increased in each group but did not show statistical differences between groups without PPD. Although implant groups showed a higher MBL in the upper jaw, only the standard dental group demonstrated a statistically significant difference. At 90 days, the OPG:sRANKL ratio and total amounts of CTSK for each group did not differ from baseline. Conclusions: Within the limitations of this study, both short and mini dental implants were achieving the same outcomes as the standard dental implants in the early period after loading.

• Journal of Periodontal and Implant Science
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• 제47권3호
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• pp.134-142
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• 2017

Purpose: This study aimed to evaluate the effects of a cetylpyridinium chloride (CPC) and tranexamic acid (TXA) mouth rinse on patients with gingivitis. Methods: This randomized, placebo-controlled, double-blind, parallel-group, clinical trial included 45 healthy adults with gingivitis, who were randomized into 2 groups. The experimental group used a 0.05% CPC and 0.05% TXA mouth rinse, and the control group used a placebo mouth rinse. The following clinical indices were assessed at baseline, at 3 weeks, and at 6 weeks: the Turesky-Quigley-Hein plaque index (QHI), the $L{\ddot{o}}e-Silness$ gingival index (GI), and bleeding on marginal probing (BOMP). The subjects used the mouth rinse during the experimental period for 20 seconds, 4-5 times daily (10 mL each time). Results: There were no significant differences in the clinical indices between the groups at baseline. In the experimental group (CPC+TXA), a statistically significant improvement was evident in the QHI, GI, and BOMP at 3 and 6 weeks. These results were similar to those observed in the control group at 3 and 6 weeks, although the change in BOMP was not statistically significant in that group. At 6 weeks, the experimental group had a significantly lower mean score for the QHI than the control group. Conclusions: This study demonstrated that a CPC and TXA mouth rinse exhibited significant antiplaque and anti-gingivitis efficacy, and had a positive effect on bleeding control when used daily for 6 weeks.