• 한국산업보건학회지
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• 제15권2호
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• pp.124-134
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• 2005

To investigate the exposure effect of polynuclear aromatic hydrocarbons (PAHs), we measured airborne total PAHs as an external dose, urinary 1-hydroxypyrene (1-OHP) as an internal dose of PAHs exposure, and analyzed the relationship between urinary 1-OHP concentration and PAHs exposure. The study population contained 44 workers in steel-pipe coating and paint manufacture industries. The airborne PAHs was obtained during survey day, and urine were sampled at the end of shift. Personal information on age, body weight, height, eniployment duration, smoking habit, and alcohol consumption was obtained by a structured questionnaire. Airborne PAHs were analyzed by the gas chromatograph with mass selective detector. Urinary 1-OHP levels were analyzed by the high performance liquid chromatograph with ultraviolet wavelength detector. For statistical estimation, t-test, ${\chi}^2$-test, analysis of variance, correlation analysis, arid regression analysis were executed by SPSS/PC (Windows version 10). The mean of environmental total PAHs was $87.8{\pm}7.81{\mu}g/m^3$. The mean concentration ($526.5{\pm}2.85{\mu}g/m^3$) of workers in steel-pipe coating industries using coal tar enamel was the higher than that ($17.5{\pm}3.36{\mu}g/m^3$) of workers in paint manufacture industries using coal tar paint. The mean of urinary 1-OHP concentration ($51.63{\pm}3.144{\mu}\;mol/mol$ creatinine) of workers in steel-pipe coating industries was the higher than that ($2.33{\pm}4.709{\mu}\;mol/mol$ creatinine) of workers in paint manufacture industries. The mean of urinary 1-OHP concentration of smokers was the higher than that of non-smokers. There was significant correlation between the urinary concentration of 1-OHP and the environmental concentration of PAHs (r=O.S48, p<0.001), pyrene(r=0.859, p<0.001), and urinary cotinine (r=0.324, p<0.05). The regression equation between the urinary concentration of 1-OHP in ${\mu}g/g$ creatinine($C_{1-OHP}$) and airborne concentration of PAHs (or pyrene) in ${\mu}g/m^3$ ($C_{PAHs}$ or Cpyrene) is: Log ($C_{1-OHP}$)=-0.650+0.889×Log($C_{PAHs}$), where $R^2=0.694$ and n=38 for p<0.001.Log ($C_{1-OHP}$)=1.087+0.707${\times}$Log(Cpyrene), where $R^2=0.713$ and n=38 for p<0.001. From the results of stepwise multiple regression analysis about 1-OHP, significant independents were total PAHs and urinary cotinine (adjusted $R^2=0.743$, p<0.001). In this study, there were significant correlation between the urinary concentration of 1-OHP and the airborne concentration of PAHs. The urinary 1-OHP was effective index as a biomarker of airborne PAHs in workplace. But it was influenced by non-occupational PAHs source, smoking.

• 한국결정성장학회지
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• 제9권6호
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• pp.601-605
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• 1999

$LiCoO_2$와 고용체 화합물인 $LiCo_{1-x}Ni_XO_2$을 고상반응법을 이용하여 제조하여 XRD, SEM, 입도분석, $^7$Li NMR을 통하여 그 구조적 cation mixing 현상을 조사하였다. 고상반응법으로 합성한 $LiCoO_2$와 $LiCo_{1-x}$$Ni_x$$O_2$의 미세결정상은 hexagonal layered structure를 보여주었고 전반적인 입도는 니켈의 함량에 따라 증가되었다. 고용체에 있어서 Ni의 함량 분율(x)이 x=0.3, 0.5, 0.7로 Ni의 양이 증가함에 따라 cation mixing 효과가 증가되었다. $^7$Li NMR의 peak frequency는 Ni의 함량이 증가함에 따라 high frequency로 shift되었고 line width는 Ni의 함량에 따라 넓어지는 양상을 보여주었다.

• 한국통신학회논문지
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• 제24권7B호
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• pp.1351-1360
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• 1999

기존의 PN 부호 초기동기 장치는 AWGN 채널에 이상적으로 설계되었으므로 주파수 선택적 레일리 페이딩 채널에서는 이상적인 구조가 아니다. 따라서 본 논문에서는 자동 임계치 제어(Automatic Threshold Control: ATC) 알고리즘을 적용한 디지틀 정합 필터링(DMF)을 기반으로 하여 직접 시퀀스 대역확산(DSSS) 방식에서의 PN 부호 초기동기 장치를 제안하고, 검출확률(PD)과 오류 경보확률(PFA)에 대한 성능을 분석하였다. 초기동기를 위한 탐색 기법은 직렬탐색기법을 고려하였으며, 성능평가를 위한 두 가지 확률은 도플러 주파수, 샘플링 주기, 평균 초기동기 시간 및 PN 칩율 등을 고려하여 주파수 선택적 레일리 페이딩 채널환경에서 유도하고 분석하였다. DMF를 기반으로 한 초기동기 시스템 모델은 시뮬레이션을 결과로부터 ATC 알고리즘을 채택한 모델이 기존의 일정 임계치 시스템보다 성능이 우수하다는 결론을 보였다.

• 한국생활과학회지
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• 제10권1호
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• pp.113-126
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• 2001

The purpose of this study was to investigate clothing behavior and ornaments wear of university students. The subject of this study consists of 241 college students who were attended in Kongju National University. SPSSWIN Program was utilized to calculated frequency(N), mean value(M) and standard deviation(SD) for statistical analysis. Differences among the populations were examined through T-test, F-test, $x^2$-test. The results of this study were as follow : 1. Clothing behavior of university students had significant difference according to sex, grade. In general, female students showed higher score than did male students in clothing interest, clothing conformity, self-estimation about clothing, clothing dependence, clothing aesthetic, clothing modesty, A first-year students had high tendency in clothing interest. 2. The wear of ornaments had significant difference according to variables. Buying the ornaments, most of students sot information in show window and emphasized on design. Male students wanted to have the ornaments of shoes, watch, hat & necklet, but female students wanted to have the ornaments of shoes, earring, necklet & hairpin. 3. Clothing behavior has Influenced university students' ornaments wear. The university students who appeared to be interested in clothes were apparently influenced by peers when selecting ornaments. Ornaments were usually bought in the department store, while belts were among the most popular choices. Students who stressed color when purchasing ornaments showed a high level of interest in and dependence on clothes. On the basic of these results, we can conclude that university students' taste in clothing behavior and use of ornaments wear depend on several different factors. Therefore, it is possible to outline the shift in clothing attitudes during adolescence. In order to understand university students' behaviour concerning clothes, much guidance and various studies on the subject are much recommended.

• 한국대기환경학회지
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• 제13권2호
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• pp.161-170
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• 1997

The concentrations of dimethylsulfide (DMS) were determined using samples collected from a station located at Kosan, Cheju Island during two field campaigns held in December 1996 and January 1997. The atmospheric DMS concentrations measured at 6-hr intervals during the entire campaign periods, after excluding a few extreme values, spanned in the range of 14 to 410 pptv with mean and 1 SD value of 127 $\pm$ 94 pptv (N=42). Between two month periods during which the field campaigns were conducted, a notable reduction in DMS levels was observed which was comparable to the dramatic shift in air temperature. A considerable difference was also noted in DMS levels, when data were grouped by day/night basis. The cause of unexpected, high day-to-night DMS ratios is best explained in terms of high efficiency of daytime source processes relative to low efficiency of nighttime sink processes due to the characteristics of the study location. The surface water DMS of the study site, although scarcely measured, also behaved similarly to its atmospheric counterpart with its range from 0.3 to 19 nM (N=11). When correlation analysis was conducted between the atmospheric DMS concentration and other concurrently determined parameters, significant correlations were observed from most basic meteorological parameters such as windspeed, relative humidy, and air temperature. However, the existence of "not-so-strong" correlations between air temperature and DMS concentrations relative to other ones indicated that the effect of temperature on DMS behavior must be reflected in more complicated manners at the study site. The sea-to-air flux of DMS was approximated through an application of the mass-balance flux calculation method of Wylie and de Mora (1996) under the assumption that sink mechanism within the marine boundary layer is in steady-state condition with its counterpart, source mechanism. Based on this estimation method, we reached a conclusion that oceanic DMS emitted from the southwest sea of the Korean Peninsula can amount to approximately 9 $\sim$ 36 Gg S $yr^{-1}$.$yr^{-1}$.

• 대한토목학회논문집
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• 제13권5호
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• pp.173-181
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• 1993

자연하천에 대한 합리적인 하천개수계획수립 및 유로의 유지관리면에서 반드시 규명되어야 할 유로만곡부에서의 정량적인 해석은 여러가지 접근방법이 있으며, 사행하천의 유로이동에 대한 예측은 도로, 교량 등의 위치선정과 기존하천구조물의 방재에 필수적이다. 하상계수가 큰 우리나라의 하천에 유로이동 예측모형을 적용할 때 유량은 기간별-지배유량을 고려하는 것이 타당할 것으로 사료되며, 본 연구대상 유역에 대한 침식계수, 유로이동에 대한 평균오차량, 하상세굴계수 등을 비교검토한 결과 유로이동을 지배하는 유량이 존재함을 알 수 있으며, 연구대상유역에서 유로이동에 대한 지배유량은 재현기간 4년에 해당하는 6,000CMS 이상으로 사료된다. 유로이동모형을 실측값이 있는 남한강의 연구대상유로에 적용하여 침식계수를 구하였으며, 계산된 침식계수를 이용하여 그 유로에서의 2000년에 대한 유로이동을 예측하였다.

• Journal of Korean Neurosurgical Society
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• 제44권1호
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• pp.1-7
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• 2008

Objective : The purpose of this study was to investigate the factors affecting the surgical outcome and to compare the surgical results between transsylvian and transcortical approaches in patients with putaminal hematomas. Methods : Retrospective review of charts and CT scan images was conducted in 45 patients (20 transsylvian and 25 transcortical approaches) who underwent open surgical evacuation of putaminal hematomas. Mean Glasgow coma scale (GCS) score and hematoma volume were $7.5{\pm}3.2$ and $78.1{\pm}29.3\;cc$, respectively. The factors affecting the functional mortality were investigated using a multivariate logistic regression analysis. In addition, surgical results between transsylvian and transcortical approaches were compared. Results : None of the patients had a good recovery after the surgery. Overall functional survival rate and mortality were 37.7% and 31%, respectively. The only risk factor for functional mortality was GCS motor score after controlling age, history of hypertension, side of hematoma, hematoma amount midline shift, presence of intraventricular hemorrhage and surgical approach (p=0.005). Even though a transcortical approach was shorter in operative time (4.4 versus 5.1 hour) and showed a higher mortality rate (40% versus 20%) and lower functional survival (45% versus 35%) compared to the transsylvian approach, the differences were not statistically significant between the two groups. Conclusion : In patients who have large amounts of hematoma and require open surgical evacuation, the only significant risk factor for functional survival is the preoperative GCS score. Cortical incision methods such as transsylvian and transcortical approaches have no influence on the surgical outcome. To decompress the swollen brain rapidly, transcortical approach seems to be more suitable than transsylvian approach.

• 대한전자공학회논문지SP
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• 제46권6호
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• pp.132-145
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• 2009

본 논문에서는 임의의 조명 상황에서 왜곡된 영상을 JND(Just noticeable difference)와 경계 보호 평탄화 필터(edge-preserving smoothing filter)를 사용하여 자동적으로 휘도 및 색상을 복원하는 기법을 제안한다. 제안된 방법은 최적의 휘도 보상, 선명한 색상 복원, 휘도 보상 시 발생되는 여러 가지 문제점의 최소화, 자동화된 매개변수 추정 그리고 하드웨어 구현을 위한 고속화 등을 목적으로 하고 있다. 이를 위하여 본 논문에서는 후광효과(HALO)나 노이즈 증폭 등의 눈에 거슬리는 결함을 제거하기 위하여 경계 보호 평탄화 필터의 효용성에 대해 보인다. 또한 제안된 색상 복원 함수는 인간시각에 근거해 자연스러운 색상의 복원과 왜곡된 색상의 보정을 수행한다. 자동화된 처리를 위하여 영상의 통계적 분석과 JND를 이용해 적합한 매개변수를 찾으며 모든 상수는 미리 정의되어 사용된다. 또한 터치스크린 카메라를 이용한 관심영역(ROI : Region of Interest) 기반 매개변수 추정기법을 사용하여 역광 사진 보정을 좀 더 효율적으로 수행한다. 객관적 평가를 위해 CMC, CIEde2000, PSNR, SSIM, 그리고 3D CIELAB 색역을 기존의 연구나 상업 제품들과 비교하였다.

• Journal of Korean Dental Science
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• 제5권1호
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• pp.29-36
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• 2012

Purpose: To investigate the effects of anterior guidance (AG) change on the working (WCP) and non-working condylar paths (NWCP), and lower incisor path (LIP) using a splint with flat (FAG) or steep AG (SAG). Materials and Methods: The samples consisted of six young adult women (mean age=$23.5{\pm}3.3$ years). Inclusion criteria were skeletal Class I and normodivergent pattern, normal overbite/overjet, minimal slide from retruded cuspal position to intercuspal position, no temporomandibular disorder signs and symptoms, mutually protected occlusion, and minimal tooth wear. After the values of natural AG (NAG) were obtained as a reference for each patient, two types of splints ($15^{\circ}$ flatter and steeper than NAG) were made. After insertion of the splints with FAG or SAG, the WCP, NWCP, and LIP were recorded five times for each patient using an ultrasonic AQR (SAM, Munich, Germany) and statistical analysis was subsequently performed. Result: NAG exhibited postero-superior movement in the WCP and did not show a noticeable immediate side shift (ISS) or difference between the eccentric (EP) and returning paths (RP) in the NWCP. FAG was associated with an irregular and excessive WCP, an increase in ISS, and a difference between EP and RP in the NWCP. SAG showed minimal WCP movement and a decrease in the extent of difference between EP and RP in the NWCP. LIP showed significant differences in EP and in RP (P<0.001, all; FAG

• 대한조선학회논문집
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• 제42권5호
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• pp.479-486
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• 2005

The final goal of shift alignment design is that the bearing reaction forces or mean pressures are within design boundaries for various service conditions of a ship. However, it is found that calculated bearing load can be substantially variable according to the locations of the effective support points of after sterntube bearing which are determined by simple calculation or assumption suggested by classification societies. A new analysis method for shaft alignment calculation is introduced in order to resolve these problems. Key concept of the new method is featured by adopting both nonlinear elastic and multi-support elements to simulate a bearing support Hertz contact theory is basically applied for nonlinear elastic stiffness calculation instead of the projected area method suggested by most of classification societies. Three loading conditions according to the bearing offset and the hydrodynamic moment and twelve models according to the locations of the effective support points of sterntube bearings are prepared to carry out quantitative verifications for an actual shafting system of 8000 TEU class container vessel. It is found that there is relatively large difference between assumed and calculated effective support points.