• 대한인간공학회지
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• 제36권4호
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• pp.281-292
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• 2017

Objective: This study aims to identify important physical design variables in designing a necklace type wearable device, and to present design guidelines to maximize comfort that a user feels upon wearing the device. Background: Interests in fitness culture and personal health are on the rise recently. In such a situation, demand for necklace type wearable devices is projected to increase a lot, as the devices enable users to use their hands freely and to enjoy various contents through connection with mobile devices. However, the necklace type wearable device's comfort was assessed to have the lowest comfort in a running situation, where human body moves up and down and left and right more than other devices wearable on other human body parts. Therefore, the usability of a necklace type wearable device was low. In this regard, studies on identification of the variables affecting user comfort upon wearing a necklace type wearable device and on physical design direction maximizing comfort and usability are needed. Method: A pretest and a main test were carried out to draw the direction of necklace type wearable device design. In the pretest, wearing evaluation on the diverse types of devices released in the market was conducted to draw physical design variables of the devices affecting comfort. Furthermore, variables significantly affecting the comfort of a device were selected through an analysis of variance (ANOVA). In the main test, anthropometry was performed, and information on anthropometric items corresponding to the design variables selected in the pretest was acquired. Based on the pretest results and the anthropometric information in the main test, the present study produced design guidelines maximizing the comfort of a necklace type wearable device with regard to major design variables upon dynamic tasks. Results: According to the pretest results, the variables having effects on comfort were the angle of side points, width, and height. Due to interactions between variables, those need to be simultaneously considered upon designing a device. Upon dynamic tasks, the angle of side points and width of a device was designed to be smaller than mean angle of the trapezius muscle and neck width, and thus attachment to human body was high. As height was designed to be larger than mean neck front and rear point width, comfort was higher due to feeling of stability. Conclusion: Because user sensitivity to comfort was high at human body's inflection points, a device needs to be designed for users not to feel high pressure on specific body parts with the device fitting human body shape well. A design considering user's situation is also required in further studies.

• Korean Chemical Engineering Research
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• 제44권5호
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• pp.444-452
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• 2006

298.15 K 및 1 atm에서 2성분계 {1,2-dichloropropane+2-(2-methoxyethoxy)ethanol} 및 {1,2-dichloropropane+2-(2-ethoxyethoxy)ethanol}에 대한 과잉몰부피와 과잉몰엔탈피를 측정하였다. 과잉몰부피를 측정하기 위한 밀도는 vibrating glass-tube 방식의 densimeter를 이용하였고, 과잉몰엔탈피는 flow mixing 형의 isothermal microcalorimeter를 이용하였다. 측정한 과잉몰부피 및 과잉몰엔탈피는 조성과 상관지어 모두 S자형을 나타내었다. 초기 2-(2-alkoxyethoxy)ethanol 의 강한 자체 회합현상으로 음의 편차를 나타내며, 할로겐화탄화수소 분자의 증가에 따라 2-(2-alkoxyethoxy)ethanol 분자간의 수소결합을 끊기 위한 에너지가 상대적 더 많이 필요함을 보여주고 있다. 실험으로부터 얻어진 $V^E_m$ 및 $H^E_m$ data는 Nelder-Mead의 simplex pattern search method를 이용하여 Redlich-Kister 다항식에 접합(fitting)하였고, Wilson, NRTL 및 UNIQUAC model을 이용하여 $V^E_m$ data와 조성과의 상관관계를 조사하였다.

• Journal of Preventive Medicine and Public Health
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• 제41권1호
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• pp.39-44
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• 2008

Objectives : This study was conducted to investigate the associations of non alcoholic fatty liver with metabolic syndrome and the serum carotenoids. Methods : This study was conducted in a general hospital in South Korea from November, 2004 to August, 2005. The study subjects were 350 sampled persons who were aged from 40 years and older (males : 180, females : 170). They were grouped into the normal, mild and severe groups according to fat accumulation in their livers, as determined by ultrasonography. We analyzed the association between non alcoholic fatty liver and metabolic syndrome by multiple logistic regression analysis and we analyzed the association between non alcoholic fatty liver and the serum carotenoids by a general linear model(ANCOVA). Results : After adjustment for the effect of potential covariates, the prevalence of metabolic syndrome was associated with fat accumulation in the liver (p trend <0.001). If the odds ratio of normal group is 1.00, then that of the mild group is 2.80 (95% C.I=1.17-6.71) and that of the severe group is 7.29 (95% C.I=2.76-19.30). The prevalence of metabolic alterations fitting the criteria of metabolic syndrome, according to the class of fat accumulation in the liver, was significantly increased, except for criteria of high blood pressure, a large waist circumference and low HDL (high density lipoprotein) cholesterol level (p trend <0.001). The level of serum ${\beta}$-carotene was decreased according to the class of fat accumulation in the liver (p trend=0.036), but the levels of serum ${\alpha}$-carotene, lycopene, ${\beta}$-cryptoxanthin and lutein were not decreased. Conclusions : This study shows that non alcoholic fatty liver was associated with metabolic syndrome and with the serum ${\beta}$-carotene level.

• 대한기계학회논문집A
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• 제34권3호
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• pp.307-313
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• 2010

본 논문에서는 지역난방에 사용되는 이형관인 벤드(bend)의 형상설계에 대한 연구를 수행하였다. 지역난방관은 강관(내부)과 폴리우레탄 보온재(중앙부) 그리고 고밀도폴리에틸렌 외관(외부)의 3개의 중공관으로 구성되며 일반적으로 $10{\sim}120^{\circ}C$ 온도범위의 물이 $16kgf/cm^2$의 내압을 가지면서 수송된다. 이에 따라 작동 중 발생하는 반복적인 열적-기계적 하중을 지탱할 수 있어야 한다. 보통 지역난방관의 벤드부에는 폼패드라고 부르는 신축흡수재가 덧씌워지는데 이 폼패드의 노후에 따른 문제가 종종 발생한다. 본 논문에서는 벤드부에서의 폼패드 노후 문제를 경감시키기 위한 대안으로 폼패드를 없앤 이중보온관의 형상 설계를 제안하였다. 제안된 설계는 벤드부 강관에 전단고리(shear ring)를 적용하는 방법으로 이때 전단고리의 최적치수는 다구찌 방법과 유한요소법을 적용하여 접근하였다. 그 결과로 전단고리의 두께와 높이, 개수 순으로 최적화 효과가 있음을 확언하였다.