• 정보처리학회논문지B
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• 제19B권1호
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• pp.1-8
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• 2012

모자이크란 여러 가지 빛깔의 재료를 조각조각 붙여서 무늬나 영상을 만드는 기법을 말하며, 최근에는 디지털 이미징 기술의 발달로 인하여 사진을 이용하여 영상을 만드는 포토 모자이크 기술들이 활용되고 있다. 본 논문에서는 적응적 타일링 및 블록 매칭을 통하여 포토 모자이크 영상을 만드는 컴퓨터 알고리즘을 제안한다. 제안한 알고리즘은 사진 데이터베이스의 생성 단계와 포토 모자이크 생성 단계로 구성된다. 사진 데이터베이스란 모자이크에 사용되는 사진(또는 타일)을 의미하며, 타일을 $4{\times}4$로 분할한 후에 각 영역의 RGB 평균값을 특징값으로 저장한다. 포토 모자이크 생성 단계는 입력 영상에 대하여 기 설정된 블록 크기로 분할한 후에 특징을 추출하는 과정, 인접한 블록들 사이의 유사도를 비교하여 병합하는 적응적 타일링 과정, 적응적 타일링을 통해 생성된 블록들을 사진 데이터베이스의 타일들과 유클리드 차이로 유사도를 비교하여 유사한 타일을 찾는 블록 매칭 과정 및 매칭된 타일의 명암값을 해당 블록의 명암값으로 교체하여 영상의 유사도를 높이는 밝기값 조정 과정으로 구성된다. 또한 인접 블록간 타일의 중복성을 최소화하는 기법을 적용하여 영상의 품질도 향상하였다. 제안한 알고리즘의 성능을 분석하기 위하여 안드레아 모자이크 소프트웨어와 비교하였고, 정량적인 분석 및 정성적인 분석에 있어서 제안한 알고리즘이 우수한 것으로 나타났다.

• Progress in Superconductivity
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• 제6권1호
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• pp.56-63
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• 2004

We consider design factors for a SQUID sensor array to construct a 52-channel magnetocardiogram (MCG) system that can be used to measure tangential components of the cardiac magnetic fields. Nowadays, full-size multichannel MCG systems, which cover the whole signal area of a heart, are developed to improve the clinical analysis with high accuracy and to provide patients with comfort in the course of measurement. To design the full-size MCG system, we have to make a compromise between cost and performance. The cost is involved with the number of sensors, the number of the electronics, the size of a cooling dewar, the consumption of refrigerants for maintenance, and etc. The performance is the capability of covering the whole heart volume at once and of localizing current sources with a small error. In this study, we design the cost-effective arrangement of sensors for MCG by considering an adequate sensor interval and the confidence region of a tolerable localization error, which covers the heart. In order to fit the detector array on the cylindrical dewar economically, we removed the detectors that were located at the corners of the array square. Through simulations using the confidence region method, we verified that our design of the detector array was good enough to obtain whole information from the heart at a time. A result of the simulation also suggested that tangential-component MCG measurement could localize deeper current dipoles than normal-component MCG measurement with the same confidence volume; therefore, we conclude that measurement of the tangential component is more suitable to an MCG system than measurement of the normal component.

• 한국식품저장유통학회지
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• 제22권4호
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• pp.553-558
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• 2015

돌산갓에서의 glucosinolates인 sinigrin의 분석법을 확립하기 위해 다양한 용매를 이용하여 추출 후 정성 정량하였다. 돌산갓을 뿌리, 줄기, 잎으로 구분하여 50% $CH_3CN$, 10% $NH_4Cl$, 60% $CH_2OH$, 70% $CH_3OH$ 을 이용해 추출시 50% $CH_3CN$이 가장 sinigrin 함량이 높게 나타났으며 나머지 용매들은 큰 차이가 없었다. 또한 갓 부위별에서 sinigrin함량은 큰 차이가 없었으며 줄기 부위의 50% $CH_3CN$추출물의 sinigrin함량이 728 ppm으로 다소 높게 나타났다. Sinigrin은 농도별로 standard curve를 작성하여 HPLC에 의한 돌산갓 부위별 sinigrin 함량을 정량화 하였고 HPLC로 분석시 UV detector 감도는 242 nm보다 228 nm에서 높게 나타났으며 228 nm에서는 줄기, 뿌리, 잎 순서로 sinigrin함량이 나타났다. 50% $CH_3CN$로 추출한 돌산갓의 chromatogram은 표준물질인 sinigrin의 retention time과 일치하였으며, 잎에서 나타난 peak는 glucosinolates인 glucoraphanin으로 확인되었다. 본 연구의 결과로부터 돌산갓에 함유된 sinigrin 분석을 위한 추출용매는 50% $CH_3CN$, UV detector 파장은 228 nm가 가장 적합하다는 것을 알 수 있었다. 또한, sinigrin의 추출 및 분석이 체계화됨으로써 돌산갓을 이용한 다양한 식품의 저장기간에 따른 sinigrin 함량변화 및 생리기능에 관한 연구에 활용 될 수 있을 것으로 판단된다.

• 한국지반환경공학회 논문집
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• 제9권1호
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• pp.47-54
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• 2008

본 연구에서는 통상 토사비탈면 안정해석시 지반강도의 입력값으로 사용되는 Mohr-Coulomb 강도정수에 대하여 지반의 함수비 조건이 미치는 영향을 조사하였다. 이를 위하여 국내 절토사면에서 채취한 두 종류의 풍화토 시료와 댐 건설시 사용되는 코아재를 대상으로 함수비 조건을 달리하며 직접전단시험을 수행하였다. 다짐시험을 통해 결정한 4단계의 함수비 조건(건조측, 최적, 습윤측, 포화)에 대해서 각 시료들의 연직응력과 최대 전단응력간의 관계로부터 산정한 Mohr-Coulomb의 ${\phi}_{peak}$과 $c_{peak}$를 비교한 결과, 전체적으로 모든 시료에 대해서 함수비가 증가함에 따라 ${\phi}_{peak}$은 큰 변화가 없으나 $c_{peak}$은 점차적으로 감소하였으며, 개략적으로 각각의 변화 비율을 분석한 결과, 함수비 조건이 건조측에서 최적, 습윤, 포화의 순서로 진행되어 변함에 따라 ${\phi}_{peak}$값은 일정하되, $c_{peak}$값은 건조측 $c_{peak}$값을 기준으로 약 25%씩 감소하는 것으로 나타났다.

• 한국산업보건학회지
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• 제16권3호
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• pp.245-253
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• 2006

We evaluated the relations among exposure and urinary levels of Cr, folate, vitamin $B_{12}$ and Hcy levels in the workers chronically exposure to Cr. Subjects were 104 male employees, 65 workers exposed to Cr in 9 electroplating plants and 39 office workers who had never been occupationally exposed to hazardous substances including Cr. The geometric mean(GM) of Cr in workplace was $0.069{\pm}0.101mg/m^3$ and urinary Cr was $0.483{\pm}0.394mg/g$ creatinine and airborne Cr concentration was significantly correlated to the urinary concentration of Cr(r=0.900, p=0.000). The geometric mean concentration of urinary Cr in control group was $0.301{\pm}0.255mg/g$ creatinine. In comparing the workers exposed to Cr with controls, significantly higher mean plasma levels were found of Hcy($11.3{\pm}4.9$ vs $9.4{\pm}4.7{\mu}mol/{\ell}$, p=0.05), but vitamin $B_{12}$ levels ($181.8{\pm}68.7$ vs $216.0{\pm}64.3nmol/{\ell}$, p=0.01) was significantly decreased. Hcy concentrations correlated positively with airborne Cr concentrations(r=0.287, p=0.004) and urinary Cr concentrations(r=0.244, p=0.015) but folate concentrations correlated negatively with airborne(r=-0.234, p=0.020) and urinary Cr concentrations(r=-0.640, p=0.090), respectively. No correlations were observed between vitamin $B_{12}$, airborne and urinary Cr concentrations. Also, Hcy concentrations correlated positively with vitamin $B_{12}$(r=0.295, p=0.0020 and negatively with folate concentrations(r=-0.196, p=0.046). The various biological(i.e. age and serum indicates) or lifestyle factors(i.e. medication, smoking, alcohol and coffee intake), also taken into account as potential confounders, did not influence the correlations found. Thus, this study found evidence that Cr might be associated with elevated plasma levels of Hcy. Furthermore, elevated plasma levels of Hcy were significantly associated with folate and vitamin $B_{12}$ concentration.

• 한국산업보건학회지
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• 제27권2호
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• pp.138-148
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• 2017

Objectives: Sleep quality is directly related to the health, quality of life and working capacity and is affected by age, gender, exercise, life habits. Gender dissimilarities in sleep quality are acknowledged. However, the gender difference in the quality of sleep in shift workers was not well known. Our aim was to study the less known gender differences in the quality of sleep of shift workers. Methods: 1,008 study subjects aged between 21 and 57 years among these, 637(525 male and 112 female workers) were daytime workers and 371(253 males and 118 female workers) were shift workers. Sleep quality was measured by self-report through the Pittsburg Sleep Quality Index(PSQI) and fatigue was measured by using the Chalder Fatigue Scale(CFS). All data was analyzed using SPSS version 19.0 program. The study was approved by the Institutional Review Board of the Occupational Safety and Health Research Institute. Results: Overall, sleep quality was found to be worse in shift workers than in daytime workers and in female than in male. Fatigue in shift female workers was significantly higher than in daytime female workers and shift male workers. In Spearman correlation analysis results, fatigue were significantly associated with gender, drink habit, regular exercise, working hours and sleep quality. With group male workers as the reference, the odds ratio(OR) for having a CFS was 2.115(${\beta}$ value=0.749, p<0.01), and subjective sleep quality, sleep latency, daytime dysfunction and PSQI were 1.541(${\beta}$ value=0.432, p<0.05), 2.297(${\beta}$ value=0.831, p<0.001), 1.798(${\beta}$ value=0.587, p<0.01) and 2.224(${\beta}$ value=0.799, p<0.01), respectively. Conclusions: Shift work played an important role in lowering the quality of sleep, and the effect was more pronounced in female workers than in male workers. Sleep quality was related to fatigue, especially sleep quality, sleep duration, sleep disturbances and daytime dysfunction were significantly related. Therefore, to improve fatigue and sleep quality of shift worker, it is necessary to improve healthy habits such as regular exercise, smoking cessation, and limited drinking. In particular, it is urgent to develop and implement a regular exercise program to reduce fatigue and improve the quality of sleep in workplace.

• 한국지반공학회논문집
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• 제18권2호
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• pp.51-64
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• 2002

굴착단계별 지반거동을 예측하기 위해 아무리 정교한 수치해석기법을 적용하여도 수치해석 모델링, 토질정수, 현장 및 시공조건 등과 관련한 불확실성으로 인해 실제 시공시 관측되는 거동은 설계단계의 수치해석을 통한 예측과 상당히 다른 결과를 나타낸다. 따라서, 굴착과정에서 발생되는 지반거동을 파악하기 위해서 항상 현장계측을 통한 관리가 이루어져야 한다. 하지만 지금까지 수행된 계측관리는 현단계 안정성만을 판단하는 절대치 관리기법에 한정되어 있어 다음 굴착단계에 대한 지반거동의 예측이 어려운 실정이다. 이러한 측면에서 본 연구는 현단계 안정성 여부를 판단하는 절대치 관리기법 이외에 역해석을 통해 다음 굴착단계의 지반거동을 예측하고 안정성을 판단하는 예측관리기법을 도입한 지반굴착 흙막이공의 정보화시공 종합관리 시스템인 TOMAS-EXCAV를 개발하였다. TOMAS-EXCAV는 SQP-MMFD의 최적화기법을 적용한 역해석 프로그램을 정해석 프로그램과 연계하여 굴착 또는 시공 초기단계에 실시된 계측결과를 토대로 주요 설계변수의 최적화를 수행함으로써 흙막이구조물 해석시 모든 불확실성을 포괄적으로 반영한다. 본 연구에서는 이에 대한 검증을 위해 흙막이 현장 2개소를 선정하여 역해석을 중심으로 TOMAS-EXCAV의 적용성을 확인하였다.

• 전자공학회논문지
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• 제51권10호
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• pp.213-220
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• 2014

시공간 분해능이 우수하고 비침습적으로 대뇌 신경활동의 측정이 가능한 뇌자도는 뇌기능 연구 및 뇌질환 진단에 유용한 진단용 의료기기이다. 순수 국내기술로 개발한 한국형 뇌자도 시스템을 임상시설(병원)에 설치하고 뇌질환 환자를 대상으로 유발자계를 측정, 분석하여 한국형 뇌자도 시스템의 임상 응용 가능성을 검토하였다. 1) 반측성 안면 경련 환자를 대상으로 소리자극에 대한 청각유발자계를 측정, 분석하여 안면신경과 청신경의 상호작용 여부 및 이명과의 연관성 검토, 2)뇌종양 환자의 정중신경 자극에 대한 체성감각 유발자계를 측정하여 뇌전증 유무에 따른 연관성 검토. 뇌자도 데이터의 분석 결과로부터 한국형 뇌자도 시스템이 뇌기능 연구 및 뇌질환 진단에 유용한 시공간적인 분석 정보를 제공할 수 있음을 시사하고 있다.

• 생물정신의학
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• 제15권1호
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• pp.5-13
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• 2008

Objectives : It was the aim of the present paper to examine the impact of the apolipoprotein E(APOE) ${\varepsilon}4$ on cognitive performance in community-dwelling elderly samples with 'questionable dementia'. Methods : Total 295 samples who were diagnosed with 'questionable dementia' in the recent year and completed the Korean version of the Consortium Establish a Registry for Alzheimer's Disease(CERAD-K) neuropsychological assessment protocol, were recruited. The CDR test established score of 0.5. Genomic DNA was extracted from the venous blood and APOE genotyping was done in this group. Their cognitive performance was compared by the occurrence of the APOE ${\varepsilon}4$ allele. Results : The impact of ${\varepsilon}4$ allele was significant in the Word List Recall Test(WLRT, F=4.511, df=1, p=0.035). The 'young-old' group aged 75 years and under had a significantly lower performance on the Word List Recall Test(WLRT, F=5.090, df=1, p=0.015), but the 'old-old' group over 75 years of age had not significantly different performance on the all the item of tests in ${\varepsilon}4$+ allele group. Conclusion : The conclusion to be drawn here is that community-dwelling elderly samples with ${\varepsilon}4$ allele in 'questionable dementia' had a significantly lower performance on the Word List Recall Test in the CERAD-K neuropsychological test batteries and the effect was prominent in the 'young-old' age group.

• 한국산업보건학회지
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• 제17권3호
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• pp.235-244
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• 2007

By comparing the proteins from the workers exposed to styrene with the ones from controls, it may be possible to identify proteins that play a role in the occurrence and progress of occupational disease and thus to study the molecular mechanisms of occupational disease. In order to find the biomarkers for assessing the styrene effects early, before clinical symptoms develop and to understand the mechanisms of adverse health effects, we surveyed 134 employees, among whom 52 workers(30 male and 22 female) were chronically exposed to styrene in 10 glass-reinforced plastic boat manufacturing factories in Korea and 82 controls had never been occupationally exposed to hazardous chemicals including styrene. The age and drinking habits and serum biochemistry such as total protein, BUN and serum creatinine in both groups were significantly different. Exposed workers were divided into three groups according to exposure levels of styrene(G1, below 1/2 TLV; G2, 1/2 TLV to TLV; G3, above TLV). The mean concentration of airborne styrene in G1 group was $10.93{\pm}11.33ppm$, and those of urinary mandelic acid(MA) and phenylglyoxylic acid(PGA) were $0.17{\pm}0.21$ and $0.13{\pm}0.11g/g$ creatinine, respectively. The mean concentration of airborne styrene in G2 and G3 groups were $47.54{\pm}22.43$ and $65.33{\pm}33.47ppm$, respectively, and levels of urinary metabolites such as MA and PGA increased considerably as expected with the increase in exposure level of styrene. The airborne styrene concentration were significantly correlated to the urinary concentration of MA(r=0.784, p=0.000) and PGA(r=0.626, p<0.001). In the 2D electrophoresis, the concentration of five proteins including complement C3 precursor, alpha-1-antitrypsin(AAT), vitamin D binding protein precursor(DBP), alpha-1-B-glycoprotein(A1BG) and inter alpha trypsin inhibitor(ITI) heavy chain-related protein were significantly altered in workers exposed to styrene compared with controls. While expression of complement C3 precursor and AAT increased by exposure to styrene, expression of DBP, A1BG and ITI heavy chain-related protein decreased. These results suggest that the exposure of styrene might affects levels of plasma proteinase, carriers of endogenous substances and immune system. In particular, increasing of AAT with the increase in exposure level of styrene can explain the tissue damage and inflammation by the imbalance of proteinase/antiproteinase and decrease of DBP, A1BG and ITI heavy chain-related protein in workers exposed to styrene is associated with dysfunction and/or declination in immune system and signal transduction