청소년 컴퓨터용 가구특성과 요구에 관한 연구

박희진,Pak, Hee-Jin 한국주거학회 2008 한국주거학회 논문집 Vol.19 No.4

According to the Korean National Statistics Office(KNSO), more than 90% of Korean adolescents aged from 15 to 19 use a computer for more than 10 hours per week. The KNSO also reveals that this age group mostly uses a computer in their own room, followed by a commercial place. It is also found that the house for the adolescent is not simply a physical environment, but is rather a center of their personal lives where their personal and social developments are formed. Therefore, the physical environment where computers are used is very important. The purpose of this study was to investigate the characteristics and needs of computer furniture for the adolescent. Data were collected through self-administered questionnaires and 414 adolescents participated. The results of this study are as follows: (1) Most of the respondents(42%) used the internet for less than one hour per day and it was used for community visits and operations, game, and chat rooms. (2) The desks where computers were used were specially designed and made of wood. Chairs were typically height adjustable with armrests and there was no task lighting for computer use. (3) The preferences of computer furniture were chairs with a high back, casters and armrests. The overall satisfaction of individual computer rooms was low. However, it is important for an adolescent to be provided with a user friendly environment for sound growth and development. Further study is therefore needed regarding environmental variables through empirical study.

에너지 효율적 트리로터 수직이착륙 무인항공기 개발

박희진,공동욱,손병락,이동하,Park, Hee-Jin,Kong, Dong-Uck,Son, Byung-Rak,Lee, Dong-Ha 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.suppl3

In the recent research technical solutions have been studied to integrate renewable energy into unmanned aerial vehicles to use it as the main power source. As the weight of the aerial vehicle body is essential for its performance, we consider to use light-weight solar cell technology. Furthermore fuel cells are also integrated create a highly energy-efficient aerial robot. In this paper, construction concept and software design of the tilt-rotor aerial vehicle GAORI is introduced which uses solar cells and fuel cells as power source. The future work direction and prognosis are discussed.

플라즈마 처리된 폴리이써설폰 막의 CO₂/N₂ 혼합가스의 투과거동에 대한 연구

박희진,노상호,배성렬,문세기,Park, Hee-Jin,Noh, Sang-Ho,Bae, Seong-Youl,Moon, Sei-Ki 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.6

폴리이써설폰 막(polyethersulfone membrane, PES)을 Ar, $NH_3$ 플라즈마로 표면 처리하고, 처리 전후의 변화를 관찰하였다. Ar 플라즈마로 처리하였을 때 O/C의 비율이 증가하며 친수성기의 도입이 확인되었고 $NH_3$ 플라즈마로 처리하였을 때 아민, 아미노기가 도입되었다. 또한 폴리이써설폰 막의 흡습성이 유지될 경우, 플라즈마 처리에 의해 표면에 형성된 극성 작용기들과 $CO_2$와의 내부반응이 증가하였다. 이로 인해 $N_2$에 비하여 $CO_2$의 용해 선택성이 증가하였고 투과도와 선택도가 동시에 향상되는 효과를 나타내었다. 플라즈마 처리된 폴리이써설폰 막에서 $CO_2$의 투과도와 ${\gamma}$(actual separation factor)에 대한 최적조건은 Ar 플라즈마 처리의 경우 10 W-2 min에서 각각 $13.19{\times}10^{-10}cm^3(STP)cm/cm^2{\cdot}s{\cdot}cmHg$와 20.12이며, $NH_3$ 플라즈마 처리의 경우 50 W-2 min에서 $15.40{\times}10^{-10}cm^3(STP)cm/cm^2{\cdot}s{\cdot}cmHg$와 20.06를 얻었다. The surface of polyethersulfone(PES) membrane treated by Ar, $NH_3$ plasma, and the effects were observed before and after the treatment. The membrane treated by Ar plasma was increased the O/C ratio and measured the hydrophilic group, and the one by $NH_3$ plasma was attached the amine group and the amino group. In addition, with the wettability of polyethersulfone membrane $CO_2$ and the polar functional groups of surface interacted increasingly. Thus by comparable increase of the soluble selectivity $CO_2$ to $N_2$ both the permeability and the selectivity of $CO_2$ was improved. The optimum condition for the $CO_2$ permeation and actual separation factor of the plasma treated membrane was as follows; the measurement of Ar-10 W-2 min plasma treatment was $13.19{\times}10^{-10}cm^3(STP)cm/cm^2{\cdot}s{\cdot}cmHg$ and 20.12, and the measurement of $NH_3$-50 W-2 min plasma treatment was $15.40{\times}10^{-10}cm^3(STP)cm/cm^2{\cdot}s{\cdot}cmHg$ and 20.06.

CIFER^®를 이용한 무인 헬리콥터의 동특성 분석 (I) - 조종기 제어 입력 데이터 획득을 위한 비행시험 -

박희진,구영모,배영환,오민석,양철오,송명현,Park, Hee-Jin,Koo, Young-Mo,Bae, Yeoung-Hwan,Oh, Min-Suk,Yang, Chul-Oh,Song, Myung-Hyun 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.6

Aerial spraying technology using a small unmanned helicopter is an efficient and practical tool to achieve stable agricultural production to improve the working condition. An attitude controller for the agricultural helicopter would be helpful to aerial application operator. In order to construct the flight controller, a state space model of the helicopter should be identified using a dynamic analysis program, such as CIFER$^{(R)}$. To obtain the state space a model of the helicopter, frequency-sweep flight tests were performed and time history data were acquired using a custom-built stick position transmitter. Four elements of stick commands were accessed for the collective pitch (heave), aileron (roll), elevator (pitch), rudder (yaw) maneuvers. The test results showed that rudder stick position signal was highly linear with rudder input channel signal of the receiver; however, collective pitch stick position signal was exponentially manipulated for the convenience of control stick handling. The acquired stick position and flight dynamic data during sweep tests would be analyzed in the followed study.

플라즈마 스프레이 (Ca, Co)-Doped LaCrO₃ 코팅층의 치밀화 및 전기전도도

박희진,백경호,Park, Hee-Jin,Baik, Kyeong-Ho 한국재료학회 2017 한국재료학회지 Vol.27 No.3

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.

논문편 : 노인들의 환경디자인 요소와 낙상위험 인지도와의 관계 및 주거내에서 낙상위험을 줄이기 위한 디자인 지침

박희진,조앤슈로이어 ( Hee Jin Pak,JoAnn L . Shroyer ) 대한가정학회 1996 Human Ecology Research(HER) Vol.34 No.6

정보채집으로의 접근 - 폭소노미 이해를 위한 개념적 틀 연구 -

박희진,Park, Hee-Jin 한국비블리아학회 2011 한국비블리아학회지 Vol.22 No.3

본 연구는 정보채집(information foraging) 이론을 적용하여 웹 정보자원을 조직, 검색, 공유하는 폭소노미 이용자의 상호작용을 체계적으로 연구, 분석하는 개념적 틀을 제시하고자 한다. 폭소노미 상호작용 이해를 위한 개념적 틀은 최종 이용자의 세 가지 정보행위간의 유기적인 관계로 구성되어 있다: (1) 태그를 활용하여 웹 정보자원을 분류하고 조직하는 태깅; (2) 폭소노미 내에서 유용한 정보 자원을 발견하고 검색하는 정보탐험; (3) 폭소노미를 통해 유사한 관심을 갖고 있는 다른 이용자를 발견하고 커뮤니티를 구성하며, 협업을 통해 새로운 정보자원을 창출해내는 지식공유. 이 틀에서 최종이용자는 정보환경에 유연적으로 적응하며 폭소노미를 통해 줄곧 관심사에 관한 정보를 수집, 모니터하며 다른 이용자와의 효율적인 공유와 검색을 위해 끊임없이 탐험하는 정보채집자(information forager)로 이해된다. 본 연구에서 제시한 개념적 틀은 이용자와 폭소노미의 역동적이고 복잡한 상호작용 현상을 포괄적으로 조망함으로써, 향후 폭소노미를 비롯한 웹 정보서비스의 유용화 연구 설계에 보다 체계적인 이론적 토대를 제공할 수 있을 것이다. This paper proposes a conceptual framework to explore the ways in which people work with in accessing, sharing, and navigating Web resources. In order to provide a better frame of a user's interaction with a folksonomy, an information foraging approach was adapted that denotes adaptive information seeking behaviors of users within human information interaction. A conceptual framework that consists of three different components from users' points of view was proposed: tagging, navigation, and knowledge sharing. This understanding will help us to motivate possible future directions of research in folksonomy and lay the groundwork for empirical research which focuses on qualitative analysis of a folksonomic and users' tagging behaviors.

조선후기 가계당 평균구수 추세 - 족보를 이용한 가족재구성을 중심으로 -

박희진 ( Hee Jin Park ) 경제사학회 2002 經濟史學 Vol.33 No.-

This paper estimates the average number of adult males per household using genealogies from 1639-1940. Efforts were made to eliminate forged entries. The number of adult males per household rose in the seventeenth century, which was followed by stagnation of the eighteenth century, and decline for most of the nineteenth century. The decline came to an end in the 1880s, when rapid increase started. Such a trend is consistent with those found in life expectancy and the incidence of adoption. The number of adult males per household is significantly and positively correlated with population during the colonial period(1910-1940).

전자빔 증착에 의한 CoNiCrAlY-YSZ 내열 코팅층의 미세조직 형성거동

박희진 ( Hee Jin Park ),박창현 ( Chang Hyun Park ),강희수 ( Hee Soo Kang ),백경호 ( Kyeong Ho Baik ) 대한금속재료학회(구 대한금속학회) 2013 대한금속·재료학회지 Vol.51 No.7

In this study, the microstructural evolution of CoNiCrAlY-YSZ duplex coating manufactured by electron beam physical vapor deposition (EB-PVD) was investigated in terms of surface and cross-sectional morphology, local distribution of alloying elements and constitutive phases. A defect-free, well-bonded CoNiCrAlY coating was formed at substrate temperatures beyond 600℃. A higher substrate temperature promoted the growth or coalescence of CoNiCrAlY columnar grains, resulting in a rougher surface. Non-uniform distribution of alloying elements in the CoNiCrAlY coating occurred along the coating thickness, which was mainly attributed to the different equilibrium vapor pressure of the alloying elements. Both CoNiCrAlY and YSZ coatings formed a well-defined columnar grain structure which grew in the direction perpendicular to the substrate surface.

이익투명성 및 정보비대칭과 자기자본비용

박희진 ( Hee Jin Park ),신호영 ( Ho Young Shin ),고종권 ( Jong Kwon Ko ) 한국회계학회 2014 회계저널 Vol.23 No.4

본 연구의 목적은 이익투명성이 높은 기업일수록 낮은 자본비용을 부담하는지를 살펴보는 것이다. 아울러 기업집단 소속여부와 정보비대칭 수준에 따라 이익투명성이 자본비용에 미치는 영향이 달라지는지를 분석한다. 이익투명성이 높다는 것은 이익정보가 기업의 경제적 가치의 변화를 잘 설명한다는 것으로 정의할 수 있으며, 본 연구에서는 Cheng and Subramanyam(2008)과 Barth etal.(2013)이 제시한 방법으로 이익투명성을 측정한다. 재무제표는 기업과 시장참여자 간의 정보비대칭을 완화하는 역할을 수행함으로써 기업의 정보위험을 감소시키는 역할을 수행한다. 재무제표에 보고되는 회계정보가 기업의 경제적 가치변화를 효과적으로 설명한다면 정보유용성은 증가할 것이며, 회계정보는 경제적 자원의 효율적 배분기능에 기여할 것이다. 투명성이 높은 이익정보가 기업의 경제적 가치변화를 보다 잘 설명한다면 이익투명성이 높을수록 기업의 불확실성에 따른 정보위험이 감소하기 때문에 시장참여자들이 요구하는 자본비용은 감소할 수 있다. 한편, 기업의 이익투명성이 낮다면 투자자들은 경제적인 의사결정을 수행하기 위해 이익정보 이외의 사적정보를 취득하고자 할 것이다. 사적정보를 취득하는 과정에서는 추가적인 비용이 발생하며, 정보의 한계취득원가가 투자자마다 상이할 경우 시장참여자 간의 정보비대칭은 증가할 수 있다. 시장참여자들이 낮은 이익투명성을 정보위험의 증가로 받아들인다면, 추가적인 프리미엄을 요구할 것으로 예상된다. 분석결과, 이익투명성이 높은 기업일수록 자본비용이 유의하게 감소하는 것으로 나타났다. 이익투명성에 따른 자본비용의 감소효과는 대규모기업집단에 소속된 기업에서 더 크게 나타났으며, 정보비대칭이 높은 상황에서는 자본비용의 감소가 더 작게 나타났다. 본 연구결과는 이익투명성이 자본비용에 미치는 영향이 대규모기업집단 소속여부 및 정보비대칭 수준에 따라 상이하게 나타난다는 결과를 제시하고 있다. 본 연구는 이익투명성에 대한 적절한 측정치 부재로 인해 관련 선행연구가 부족한 시점에서 이익 투명성이 자본비용에 미치는 영향을 실증적으로 분석하였다는 점에서 의미를 갖는다. 아울러 이익투명성에 따라 기업의 자본조달비용이 감소할 수 있다는 실증적인 증거를 제시한다는 점에서 본 연구의 결과는 경영자뿐만 아니라 투자자 및 감독기관 등에게 중요한 시사점을 제공할 것으로 판단된다. The purpose of this paper is to examine whether firms with higher earnings transparency have lower cost of capital in the capital market. We also examine how a relation between earnings transparency and the cost of capital is affected by Korean business group and information asymmetry. Earnings transparency is the degree to which earnings explains a change in the firm value. We measure earnings transparency based on prior studies of Cheng and Subramanyam(2008) and Barth et al.(2013). Financial reporting mitigates information risks of the firm by reducing information asymmetry between the firm and market participants. If accounting information explains a change in the firm value effectively, this can be the evidence of information usefulness and contribute to the efficient allocation of economic resources. Higher transparency in earnings means a better explanation of a change in the firm value. Thus, we expect higher transparency in earnings lower the cost of capital by reducing information risks from uncertainty of business. On the other hand, we expect that investors of the firm with low earnings transparency obtain a private information rather than earnings for financial decisions. Additional expenses can incur in the process of obtaining the private information, and information asymmetry among the market participants can deepen if marginal costs of information for each investor vary. As a result, market participants will ask for an additional premium as the consideration for lower earnings transparency which means higher information risk. Our results show that earning transparency measures are negatively related to the cost of capital. Higher transparency in earnings is significantly associated with lower cost of capital. We also find that firms with business group affiliation have a larger decrease in the cost of capital, while those with higher information asymmetry show a smaller decrease in the cost of capital. Our study is distinguished from prior studies because we empirically analyze the effect of earnings transparency on cost of capital. In addition, we find empirical evidence that a relation between earnings transparency and the cost of capital is affected by Korean business group and information asymmetry. Overall, our study suggests the importance of earnings transparency in terms of the cost of capital.