• 대한전자공학회논문지SD
• /
• 제39권10호
• /
• pp.16-24
• /
• 2002

본 논문에서는 광학적으로 투명한 ITO를 에미터 전극을 갖는 InP/InGaAs HPT를 제작하였고 제작된 HPT의 전기적 특성을 분석하기 위해 확장된 Ebers-Moll 방정식을 이용하여 DC 모델파라미터들을 추출하였다. 또한 초고속 전자소자로서 사용되어지는 InP/lnGaAs HBT를 제작하여 그 전기적 특성을 HPT와 비교하였다. 제작된 HPT의 에미터접촉 저항(RE)값이 6.4Ω으로 HBT와 거의 동일함은 물론 HPT의 모든 UC 모델 파라미터들이 HBT 와 유사함을 알 수 있었다.

• Educational Technology International
• /
• 제10권1호
• /
• pp.107-135
• /
• 2009

The purpose of this paper is to review a variety of challenges facing the Human Performance Technology (HPT) in supporting knowledge workers' performance, and to explore possible HPT models for knowledge workers. The first section of this paper investigates the core attributes and major models of HPT as a foundation. While HPT has a lot of strengths in terms of systemic, systematic, methodologically eclectic, evidence based, and results oriented approaches, some pitfalls - which could be detected if these principles were mindlessly applied to problem areas - are explored. The second section presents some considerations such as analysis, intervention design, and leadership that HP technologists need to take in order to make HPT a better field of practice for knowledge workers. The author also suggests a tentative diagnostic model and a process model for knowledge workers, core principles of which are based on systems thinking, in particular Senge's the fifth discipline and Checkland's soft systems methodology. The importance of formative evaluations to improve these models is noted as a conclusion.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제51권11호
• /
• pp.546-550
• /
• 2002

In this paper, Heterojunction phototransistors(HPT's) with an optically transparent ITO emitter contacts were fabricated. The ITO ohmic contacts were realized by employing thin imdium layer between the ITO and $n^+$-InP layers. The ITO contact was annealed at $250^{\circ}C$. The specific contact resistance of about $6.6{\times}10^{-4}{\Omega}cm^2$ was measured by use of the transmission line model (TLM). Heterojunction bipolar transistors (HBTs) having the same device layout were fabricated to compare with HPTs. The DC characteristics of the InP/InGaAs HPT showed the similar electrical characteristics of the HBT. Emitter contact resistance($R_E$) of about $6.4{\Omega}$ was extracted, which was very similar to that of the HBT. The optical characteristics of HPT's were generated by illuminating the device with light from $1.3{\mu}m$ light. It showed that HPT's can be controlled optically.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
• /
• pp.13-16
• /
• 2001

InP/InGaAs Heterojunction phototransistors(HPT's) with an optically transparent ITO emitter electrode were fabricated and characterized. At the same time, heterojuntion transistors(HBT's) having the same device layout were fabricated. By comparison with InP/InGaAs HBT's, the do characteristics of InP/InGaAs HPT's showed the similar electrical charateristics of HBT's. the model parameters of the device were extracted and compared.

• Ocean Systems Engineering
• /
• 제7권1호
• /
• pp.21-38
• /
• 2017

In real sea environments, excessive dynamic axial tension variations can be exerted on the top-tensioned risers (TTRs) and lead to structural integrity issues. The traditional riser-tension-variation analysis, however, by using parametric formulation is only conditionally valid under certain strict limits and potentially underestimates the total magnitudes of tension variations. This phenomenon is especially important for the long stroke tensioner in dry-tree semisubmersible with larger global heave motion and longer stroke. In this paper, the hydro-pneumatic tensioner (HPT) is modeled in detailed component-level which includes a set of hydraulic and pneumatic components. The viscous fluid frictional effect in the HPT is considered. The main objectives are (i) to develop a detailed tension variation model of the HPT; (ii) to identify the deviations between the conventional parametric formulation and component-level formulation; (iii) to numerically analyze the tension variation of long stroke tensioner in a dry-tree semisubmersible (DTS). The results demonstrate the necessity of component-level formulation for long stroke tensioner in the development of DTS.

• 서비스연구
• /
• 제2권1호
• /
• pp.1-11
• /
• 2012

그 동안 IT서비스 업체들은 국내시장을 중심으로 고객사의 정보시스템 구축을 근간으로 하는 IT서비스를 제공하는 기업으로 자리매김해왔다. 그러나 IT가 다양한 산업기술들과 융합하여 산업간 컨버전스, Intelligence, Mobility를 가능하게 하는 기술인 스마트기술로 변모함에 따라, 그에 맞춰 IT서비스 사업모델도 그 영역이 점차 다양화되어 가고 있다. 본 논문에서는 이와 같은 트랜드에 맞추어 기업 내부적으로 기술의 다양화에 따른 서비스 전문화와 서비스 혁신을 추구하기 위해서 수행공학(HPT; Human Performance Technology)을 적용한 사례를 제시하고자 한다. 즉, 수행공학을 통하여 IT서비스의 사업방향을 스마트 기술을 중심으로 하는 방향으로 변화시키고, 사업을 수행하는 임직원들의 일하는 방법을 변화시키는 노력과 관련된 LG CNS사의 교육 프로그램 개발방법의 혁신 사례를 소개하고자 한다.

• 한국도서관정보학회지
• /
• 제40권1호
• /
• pp.433-449
• /
• 2009

본 연구는 초 중등학교 교육현장에서 실시되고 있는 도서관활용수업이 어떠한 저해요인에 의해 활성화되지 않는지 원인을 분석하여 해소방안을 제시하기 위한 연구로 첫째, 도서관활용수업방법의 실증적 개선을 위한 평가 분석의 모형을 인간수행공학모형을 기반으로 재구성하였으며 둘째, 도서관활용수업에 관한 기존 연구의 이론적 토대를 기초로 실태를 파악하고 도서관활용수업의 바람직한 수행목표를 도출하였으며 셋째, 실제 연구대상학교를 중심으로 재구성된 인간수행 공학모형을 적용하여 도서관활용수업을 저해하는 요인을 도출하고 분석기법에 따라 수행요인을 분류하여 저해요인의 해소방안을 제시하였다. 연구의 결과 제시된 도서관활용수업 저해요인의 해소방안으로는 도서관활용수업에 대한 명확한 기대치 제공과 학습목표의 정확한 기술, 도서관활용수업 지원체제 구축, 교사들의 외적 동기 유발 시스템 개발, 다양한 도서관활용수업 프로그램 개발, 그리고 학교장과 일선 교사들의 도서관활용수업에 대한 인식전환 등으로 요약할 수 있으며 학교도서관매체센터가 도서관활용수업의 활성화로 인해 학교교육의 핵심적 역할을 수행할 수 있기를 기대한다.

• 수산해양기술연구
• /
• 제43권1호
• /
• pp.12-27
• /
• 2007

This fundamental studies on for the productivity improvement and laborsaving of purse seine fishery. Given the difficulty posed from the distortion of net shape caused by the external forces, such as tide, at the time of shooting and pursing, we set the 4 steps of 0, 2, 4 and 6cm/sec in flow velocity in the flume tank for the experiment in order to examine those characteristics. We used two model seines designed on the scale of 1 to 180 based on the power block seine, which is the mackerel purse seine generally used in the near sea of Jeju Island and triplex seine, which is the mackerel purse seine of one boat system fishing expected in the future, for the experiment, and interpreted the characteristics of several motion in water, such as the shape of seine, the change in tension and area during pursing and its the analysis results are as follows. Though the experiment could be conducted up to 6cm/sec of flow velocity that was defined, the experiment could not go on because of the severe distortion in the seine at the flow velocity in excess of 6cm/sec. As for the depth of leadline and reduction rate of side area of seine when the pursing is connected, P seine turned out to be slightly higher than T seine, and the hauling speed and reduction rate of upper area of seine were found similar to each other. The correlation between the hauling time (Ht) and depth of lead line (Dhp, Dht) of P seine and T seine can be expressed by the equation, that is, Dhp=(0.99Pt-7.63)Pt+69.01, Dht=(1.03Pt-7.73)Pt+66.74. The correlation between the hauling time and hauling velocity (Hpp, Hpt) can be expressed by the equation, that is, $Hpp=-0.06Ht^2+0.88Ht+0.78,\;Hpt=-0.05Ht^2+0.81Ht+0.98$ here, Pt is pursing time. And the correlation between the pursing time and the reduction rate of side area (sArp, sArt) can be expressed by the equation, that is, $sArp=-0.48Pt^2+14.79Pt-16.74,\;sArt=-0.45Pt^2+14.56Pt-16.48$. The reduction rate of upper area of seine (tArp, tArt) can be expressed by the equation, that is, $tArp=0.34Pt^2-0.66Pt-0.74,\;tArt=0.34Pt^2-0.27Pt-1.80$. In addition, the correlation between the pursing time and tension of purse line (Tep, Tet) can be expressed by the equation, that is, $Tep=2.79Pt^2+2.26Pt-0.60,\;Tet=2.14Pt^2+8.08Pt-27.50$.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
• /
• pp.9-12
• /
• 2000

InP/lnGaAs heterojunciton phototransistors (HPTs) with transparent emitter contacts were fabricated and characterized. Indium Tin Oxide was RF sputtered for the emitter contacts. By comparison with InP/InGaAs HBTs, the dc characteristics of InP/lnGaAs HPTs demonstrated offset voltage due to ITO emitter contacts and similar common emitter current gain. The model parameters were extracted and a simple SPICE simulations were performed.

• Tribology and Lubricants
• /
• 제36권2호
• /
• pp.105-115
• /
• 2020

This paper presents a numerical study on the rotordynamic analysis of a dual-spool turbofan engine in the context of blade defect events. The blades of an axial-type aeroengine are typically well aligned during the compressor and turbine stages. However, they are sometimes exposed to damage, partially or entirely, for several operational reasons, such as cracks due to foreign objects, burns from the combustion gas, and corrosion due to oxygen in the air. Herein, we designed a dual-spool rotor using the commercial 3D modeling software CATIA to simulate blade defects in the turbofan engine. We utilized the rotordynamic parameters to create two finite element Euler-Bernoulli beam models connected by means of an inter-rotor bearing. We then applied the unbalanced forces induced by the mass eccentricities of the blades to the following selected scenarios: 1) fully balanced, 2) crack in the low-pressure compressor (LPC) and high pressure compressor (HPC), 3) burn on the high-pressure turbine (HPT) and low pressure compressor, 4) corrosion of the LPC, and 5) corrosion of the HPC. Additionally, we obtained the transient and steady-state responses of the overall rotor nodes using the Runge-Kutta numerical integration method, and employed model reduction techniques such as component mode synthesis to enhance the computational efficiency of the process. The simulation results indicate that the high-vibration status of the rotor commences beyond 10,000 rpm, which is identified as the first critical speed of the lower speed rotor. Moreover, we monitored the unbalanced stages near the inter-rotor bearing, which prominently influences the overall rotordynamic status, and the corrosion of the HPC to prevent further instability. The high-speed range operation (>13,000 rpm) coupled with HPC/HPT blade defects possibly presents a rotor-case contact problem that can lead to catastrophic failure.