단일 구형 기포의 수학적 모델에 대한 수치적 해석 모델

강동근,양현익,Kang, Dong-Keun,Yang, Hyun-Ik 한국생산제조학회 2010 한국생산제조학회지 Vol.26 No.1

Cavitation is described by formation and collapse of the bubbles in a liquid when the ambient pressure decreases. Formed bubbles grow and collapse by change of pressure, and when they collapse, shockwave by high pressure is generated. In general, bubble behavior can be described by Rayleigh-Plesset equation under adiabatic or isothermal condition and hence, phase shift by the pressure change in a bubble cannot be considered in the equation. In our study, a numerical model is developed from the mathematical model considering the phase shift from the previous study. In the developed numerical model, size of single spherical bubble is calculated by the change of mass calculated from the change of the ambient pressure in a liquid. The developed numerical model is verified by a case of liquid flow in a narrow channel.

인간공학 관점에서의 심박측정 웨어러블 피트니스 트래커 형태인자(form factor) 연구

강동근(Kang, Dong Geun),정도성(Jung, Do Sung) 한국디지털디자인협의회 2014 디지털디자인학연구 Vol.14 No.4

현재 웨어러블 디바이스는 디지털 기기의 시장에서 가장 큰 화두로 떠오르고 있으며, 일상생활에 많은 변화를 가져다 줄 것으로 내다보고 있다. 이중 웨어러블 디바이스는 웨어러블 피트니스 트래커 분야가 가장 커져 있고, 가속계 센서를 사용하여 활동량만을 보여 주는 기능에서 더 나아가 다양한 센서를 이용하여 생체정보 수집으로 발전되고 있다. 운동의 성격에 따라 이 데이터들을 이용하여 사용자가 원하는 정보들을 제공하여 주는 것에 이르렀으며, 그로 인해 웨어러블 피트니스 트래커의 형태인자가 손목에 차는 형태를 중심으로 다양한 형태로 개발되어지고 있다. 그리하여 현재 운동 중 신체 어느 부위에 착용을 해야 인체공학적으로 사용편의성이 높은가에 대한 연구가 요구된다. 본 연구는 시장에 나온 제품을 조사하여 손목착용형, 가슴착용형, 이어폰형으로 형태인자를 분류하였고 현재 피트니스 트래커를 이용하는 사용자의 운동행태를 파악하여 걷기, 달리기, 자전거타기로 분류하였다. 웨어러블 관련 선행연구를 분석하고 전문가 집단토론을 통해 심미성, 착용성, 기능성으로 인간공학 평가척도 원칙을 체계화 하였으며, 각 형태인자의 사용할 때 행위나 제품의 구성요소를 파악하여 위 평가원칙으로 토대로 심층 인터뷰를 진행하여 현재 출시된 형태인자들 중 어떤 유형이 가장 편리한가에 대한 비교평가를 하였다. 이는 향후 피트니스 트래커를 개발 시 사용자가 요구하는 운동방법에 적합한 인체공학적 형태인자를 개발에 있어 지침이 될 수 있을 꺼라 생각한다. Currently, wearable devices are emerged as a hot topic in the digital device market and it is expected to bring a lot of changes in daily life. Fitness tracker is the largest field of wearable devices and it has been developed from the feature that shows only the activity by using the accelerometer sensor to the feature that collects biometric data using a variety of sensors. Depending on the character of the exercise, users can be provided with information what they want so that form factor of the fitness tracker has been developed in various forms, mainly in the form of worn wrist. Thus, research is required for the higher ergonomic ease of use according to where fitness tracker should be worn in any area of the body during exercise. This study categorizes the form factor into worn wrist type, worn chest type and ear phone type by researching the market appeared products. By analyzing the movement patterns of users currently using fitness tracker, this study categorizes them into walking, running and riding bicycle. This study analyzes the advanced research and through focus group interview, it systematizes the rating scale of human engineering : aesthetics, wearability and functionality. To grasp activity and product component when using each form factor, it did in-depth interview based on upper test principle. It conducts comparison evaluation that which type of forms is more usable and comfortable among currently appeared products. This study will become a milestone about developing human engineering form factor that is suitable for way of user-need exercise when developing fitness tracker.

세계화와 기업 간 생산성 불균등도

강동근(Kang, Dong Keun),김종일(Kim, Jong Il) 동국대학교 사회과학연구원 2015 사회과학연구 Vol.22 No.1

본 연구에서는 소득불평등 지수인 지니계수를 이용하여 제조업부문에서 산업별 기업 간 생산성 뷸균등도의 추이를 분석하고, 이러한 기업 간 생산성 불균등도에 세계화, 자본자유화, 기술혁신 등이 미치는 영향을 분석하였다. 분석의 주요 결과는 다음과 같다. 첫째, 기업 간 생산성불균등도의 전체적인 추이는 꾸준히 상승하는 형태였으며, 경제위기 시에 기업 간 생산성 불균등도가 더 심화되고 있었다. 둘째, 산업에 관계없이 전 산업에서 기업 간 생산성 불균등도가 확대되고 있었으며, 경공업에 속하는 산업에서의 불균등도 심화가 두드러지게 나타나고 있었다. 셋째, 기업 간 생산성 불균등도에 미치는 영향을 분석한 결과, 세계화가 기업 간 생산성 불균등도 심화에 유의한 영향을 미치는 것으로 확인되었다. This paper applies the measures of income distribution to the case of productivity distribution of firms to investigate the productivity dispersion of firms in Korea from 1990 to 2013. This paper estimates Gini coefficient by using the firm-level data from KIS VALUE and examines the effects of globalization on productivity inequality using panel data. The main findings are as follows. First, the productivity dispersion of firms has been widened in terms of Gini coefficient since the 1990s. Second, the productivity dispersion of firms has been widened regardless of industry. Third, the empirical results show that export, outward direct investment and R&D variables may play an important role for productivity dispersion.

옐로카펫 설치효과에 대한 조사연구 - 어린이 횡단대기 행동을 중심으로 -

강동근 ( Kang Dong-keun ) 한국도로교통공단 2017 교통안전연구 Vol.36 No.-

Domestic traffic accidents in children have been steadily declining but are still insufficient. In this study, we conducted a questionnaire survey and a field survey of the Yellow Carpet for the purpose of verifying the installation effect of Yellow Carpet, which is one of the measures to reduce children's traffic accidents. As a result of the questionnaire survey, the overall effect of the Yellow Carpet was evaluated positively. Especially, the evaluation of the person who knew the Yellow Carpet in advance was more positive than the case of not. As a result of the field survey, the rate of waiting in the Yellow Carpet of the crosswalk where the Yellow Carpet was installed was high, and the rate of waiting in the Yellow Carpet of the children was higher than that of the middle school student and above. This is a result of showing the feasibility of installing the carpet. The results of this study have demonstrated the necessity and effectiveness of Yellow Carpet for children's traffic safety, especially crossing accident prevention. In particular, considering the positive result of the Yellow Carpet awareness and the waiting behavior of the children on the crosswalk, it is believed that the installation of the Yellow Carpet is secured.

식품안전 관련 규제 및 분쟁 사례의 유형별 분석

강동근 ( Dong Kun Kang ) 영남대학교 법학연구소 2015 영남법학 Vol.0 No.41

식품위생법 상 식품안전에 관한 규제는 크게 행정적 규제, 형사적 규제로 나눌 수 있다. 행정적 규제는 영업허가에 관련된 규정, 사전예방적 규정, 사후제재적 규정으로 나누어 볼 수 있는데, 식품안전과 관련하여서는 사전예방적 규정 및 사후제재적 규정이 의미가 있다. 형사적 규제는 유해식품 판매, 허가사항위반 등에 관한 처벌 규정이 주류를 이루는 것으로 이해된다. 다만, 매년 행정사건 수가 3,000여 건을 웃돌고, 형사사건 수가 15,000여건 내외에 이르는 것에 반해 대법원 판결로 확인할 수 있는 식품위생법 사건 수는 상대적으로 매우 적은 편인데, 이는 수범자의 대부분은 영세한 상인인 경우가 많다는 점이 영향을 미친 것으로 생각된다. 2000년 이래 대법원에서 판단된 주요 식품위생법 사건은, 크게 식품위생법규정의 해석이 문제된 유형, 위임입법의 범위가 문제된 유형, 처분청의 재량권행사 범위가 문제된 유형, 식품위생법과 타 법률과의 관계가 문제된 유형, 식품의 안전성이 타 법률에서 문제된 유형 등으로 일별 할 수 있다. 이들 각 유형별 판례 분석을 통하여 법령 해석이 문제된 경우가 절대 다수를 차지하고 있음을 확인할 수 있는데, 이는 사회 변화로 인해 법령 제정 당시에는 미처 예상하지 못하였던 행위 태양이 나타남에 따라 발생하는 자연스러운 모습으로 생각된다. 또한, 법원이 식품위생법 상 규제적 규정을 국민의 생명·신체·안전에 대한 보호 범위를 넓히는 방향으로 해석하고 있음을 확인할 수 있다. Under the Food Sanitation Act, regulations on food safety are largely divided into administrative regulation and criminal regulation. Administrative regulation may be sub-divided into regulations on business permits, preventive regulations, and ex post facto sanction regulations. Preventive regulations and ex post facto sanction regulations are meaningful in regards to the food safety issue. It is understood that criminal regulations mostly include punitive regulations on the sale of harmful food and the violation of permits. However, while the number of administrative cases is over 3,000 and the number of criminal cases amounts to nearly 15,000 each year, the number of Food Sanitation Act cases that can be verified by the Supreme Court decisions is relatively small. This may be due to the fact that most of those who are convicted are petty merchants. Major cases involving the Food Sanitation Act decided by the Supreme Court since 2000 may be largely categorized into the following types: issues regarding the interpretation of the Food Sanitation Act provisions issues regarding the scope of delegated legislation; issues regarding the scope of discretionary rights exercised by disposition authorities; issues regarding inter-relations between the Food Sanitation Act and other laws; and food safety being a issue in other laws, etc. The analysis of precedents of thesetypes shows that an absolute majority of cases involves issues regarding the interpretation of legislation. This appears to be a natural ramification as the types of acts that were not anticipated at the time of the enactment emerge as a result of social changes. It also confirms that the court interprets the restrictive regulations under the Food Sanitation Act in the direction of extending the protective scope of the public’s life, health and safety.

운동별 심박측정 웨어러블 헬스케어 기기 형태인자(form factor)의 유형별 사용편의성 연구

강동근(Kang, Donggeun),정도성(Chung, Dosung) 인제대학교 디자인연구소 2015 Journal of Integrated Design Research (JIDR) Vol.14 No.1

연구배경 본 연구는 사용편의성적 측면에서 심박측정 웨어러블 헬스 케어 기기의 형태인자(form factor)들 중 어떤 유형이 가장 편리한가에 대한 분석 내용을 제시하고자 한다. 연구방법 논문의 구성은 첫 번째로 형태인자(form factor)와 사용편의성의 평가요소인 사용편의성에 대한 이론을 습득하고, 자료조사를 바탕으로 심박측정 웨어러블 헬스케어 기기의 형태인자(form factor)를 정의하였다. 둘째, 현재까지 연구되어진 문헌들은 토대로 심박측정 웨어러블 헬스 케어 기기 사용편의성을 평가하기 위한 원칙에 대한 정의와 심박측정 웨어러블 헬스 케어 기기의 사용행태, 디자인 요소들 FGI (focus group interview), 심층면접조사를 통하여 도출하였다. 셋째, 추출된 심박측정웨어러블 헬스 케어 기기 사용원칙과 사용행태 디자인 요소들을 바탕으로 설문조사를 시행하였다. 결과에 대한 분석을 통하여 그에 따른 디자인 방향성을 제시하였다. 출시한 제품을 분석한 결과 심박측정 센서의 위치에 따라 형태인자(form factor)가 분류되는 것을 알았으며 총 3가지 형태인자(form factor)로 나눌 수 있었다. 사용편의성측면에서 어떤 형태인자(form factor)가 사용할 때 사용편의성 관점에서 사용성의 만족도가 높은지에 대한 답을 얻기 위하여 설문조사를 실시하고 그에 따른 데이터에 대한 분산분석을 진행하며 그 분석 값에 따른 결과의 이유를 알기 위해 심층면접을 진행하였다. 연구결과 그 결과 향후 심박측정 웨어러블 헬스 케어 기기 사용편의성관점에서 봤을 때 걷기, 뛰기, 자전거타기 등 운동 상황과 일상생활에서 심미성과 착용감에 대하여 깊은 관심을 두고 개발해야 될 필요성 보였다 결론 현재 연구에 응답한 사용자들은 스마트워치에서 심미성과 착용감이 높게 나타났다. 그렇지만 길이 고정하는 방식과 높은 강도에서 보다 효과적인 정보전달을 위한 사용성 향상을 위한 개선의 필요성이 보였다. Background This study is to provide analysis about what type is the most convenient one among the form factors of heart rate measuring health care device in terms of ergonomics. Methods First of all, we offer a chance to learn the theory about convenience, which is a form factor and ergonomic evaluation criteria, and define form factors of heart rate measuring wearable health care device based on the research data. Secondly, we figured out the definition of the principals to evaluate the convenience of heart rate wearable health care device based on the research papers available thus far, and current ways of using heart rate measuring wearable health care devices and design elements through FGI (focus group interview), and in-depth interviews. Thirdly, we performed a survey based on the extracted way of use for the heart rate measuring wearable health care device and design elements based of way of usage. We provided the direction of design throughout the analysis of the results. As a result, we found that form factors are classified based on the location of heart rate measuring sensor, and we were able to divide it into 3 form factors. Ergonomically, we performed survey to find the answer which form factors have higher satisfaction of usability, and proceed variance analysis based on the data, and perform in-depth interview to find out the reasons for the results based on the analyzed values. Conclusion As a result, necessity of further studies in aesthetic impression and wearing sensation on walking, running, riding a bike with heart rate wearable health care device are required in the future Results Current users participated in this study show high levels of aesthetic impression and wearing sensation with the wrist type. However, they seems to need to improve for more effective transmission of information in the way of length fixation type and high-dense type.

아토피 피부염 환자에서의 혈중 호산구 및 혈청 IgE 검사에 관한 연구

강동근(Dong Geun Kang),박천욱(Chun Wook Park),이철헌(Cheol Heon Lee) 대한피부과학회 1992 大韓皮膚科學會誌 Vol.30 No.1

The peripheral blood eosinophil and serum IgE level in 53 patients with atopic dermatitis (AD) were measured. The patients were divided into 2 groups by severity(mild and severe grous) and into 3 groups by the associated respiratory atopic deseases and/or their family history : respiratory group(patient, with both AD and respiratory atopy), family history group (patient with both AD and family history of respiratory atopy), and atopic group(patient with neither respiratory atopy nor family history of respiratorv atopy). We designed to study which factors are important in the elevation of serum IgE and peripheral blood eosinophil level in AD, and to know possible relationships between the serum eosinophil and IgE level and the several groups of AD. The results are as follows : 1. Peripheral eosinophil counts were higher in severe group(224.8/mm) than in mild group (180.0/mm)(p<0.05). 2. Peripheral eosinophil counts were 220.0/mm in atopic group, l65.0/mm in family history group, and 332.4/mm in respiratory group, but there was no stitistically significant difference among 3 groups. This suggests that concomitant respiatitiry atopy or a family history of respiratory atopy is not an important factor in the elvation of peripheral blood eosinophil counts in AD. 3. Serum IgE was higher in severe group(443.2IU/ml) than in mild group(231.5IU/ml)(p<0.05). 4. Serum IgE level in respiratory group(754.6IU/ml) were signifiiantlly higher than in atopic (286.6IU/ml) or family history group(342.0IU/ml)(p<0,01). But there was no significant. difference between family and atopic group. This result suggests that concomittent respiratory atopy is a potential factor in elevation of serurn Igi in AD. 5. Slightly high correlation between peripheral blood and IgE level appeared in all 53 patients (r=0.434) and severe group(r=0.480). But, respiratory group(r=0.060), family history group(r=0.111) and atopic group(r=0.202) showed poor relationships. (Kor J Dermatol 1992; 30(1): 51-56)

경증치매노인의 기능적 체력 및 인지기능 향상을 위한 복합 수중운동프로그램 개발

강동근 ( Dong Keun Kang ),박정연 ( Jeong Yeon Park ),정주하 ( Joo Ha Jung ),박정준 ( Jung Jun Park ) 한국운동생리학회 2015 운동과학 Vol.24 No.4

PURPOSE: Aquatic exercise is popular among the elderly because its stress on joint is less compared to other exercises. The purpose of this research was to determine the effect of combined aquatic exercise with music therapy, art therapy and learning therapy on improvements of functional fitness and cognitive function in elderly with mild dementia. METHODS: Twenty two women, aged 65 to 74, participated in this study. They were randomly divided into combined aquatic exercise group(CAEG, n=12) or normal aquatic exercise group(NAEG, n=10). Both group performed exercise 60 min/day, 3 days/week, for 16 weeks at the intensity of 10-13 RPE. The variables of funcional fitness test and CERAD-K``s 10 task tests were used to measureed all the subjects. All data was analyzed by independent t-test, two-way repeated ANOVA and paired t-test by using SPSS 22.0. RESULTS: In the case of functional fitness, the CAEG improved significantly in 2 kg dumbbell curl, 2.44 m up-and go, 6-min walk and the NAEG improved 2 kg dumbbell curl, 2.44 m up-and go. In the case of cognitive function improved significantly all 10 task tests, while NAEG was no significant difference all 10 task tests. CONCLUSIONS: It is concluded that the effect of CAEG is superior to NAEG in improvements of functional fitness and cognitive function by increasing sense of sight, hearing, touching, memorizing. Thus, it suggests that combined aquatic exercise is an appropriate exercise, especially for elderly with mild dementia.

단일 구형 기포의 수학적 모델에 대한 수치적 해석모델

강동근(D.K. Kang),양현익(H.I. Yang) 한국생산제조학회 2010 한국생산제조시스템학회 학술발표대회 논문집 Vol.2010 No.4

단일 구형 기포의 수학적 모델에 대한 수치적 해석 모델

강동근(Dong-Keun Kang),양현익(Hyun-Ik Yang) 한국생산제조학회 2010 한국생산제조학회지 Vol.19 No.6

Cavitation is described by formation and collapse of the bubbles in a liquid when the ambient pressure decreases. Formed bubbles grow and collapse by change of pressure, and when they collapse, shockwave by high pressure is generated. In general, bubble behavior can be described by Rayleigh-Plesset equation under adiabatic or isothermal condition and hence, phase shift by the pressure change in a bubble cannot be considered in the equation. In our study, a numerical model is developed from the mathematical model considering the phase shift from the previous study. In the developed numerical model, size of single spherical bubble is calculated by the change of mass calculated from the change of the ambient pressure in a liquid. The developed numerical model is verified by a case of liquid flow in a narrow channel.