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FR-4 composite 기판의 성부 구성비에 따른 광대역 유전상수 모델 및 전송 특성 해석
홍정기,김성일,이해영 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.12
In this paper, we modeled the complex dielectric constant and analyzed the projpagation characteristics of a FR-4 composite substrate with different compositions. From the wideband dielectric modeling and the propagation loss analysis of FR-4 composites that consists of FR-4 resin and E-glass reinforcement,we have found that the propagation loss and velocity increase with the volume fraction of FR-4 resin above 1 GHz. These results are helpful in determining to deisgn optimum substrate composition ratio and cross-sectional geometry of high-speed and high-density transmission line.
현상학적 도체 손실 등가 기법을 이용한 고속 전송선의 펄스 전송 특성 해석
홍정기,이해영,민형복 대한전자공학회 1995 전자공학회논문지-A Vol.32 No.3
The phenomenological loss equivalence method incorporated into the wideband lossy transmission line model is applied to the characterization of high desity digital transmission lines. The pulse propagation characteristics are analyzed using the calculated frequency characteristics and the discrete Fourier transformation. This approach has been verified by comparing the calculated frequency characteristics with the FEM and the esperimental results. This method is very suitable for computer-aided analysis of high density/high speed interconnection circuits because of the simple calculation as well as the calculation accuracy. We have found that pulse ftransmission speed and dispersion of hgih density digital transmission lines can be optimized by managing the conductor and dielectric losses in addition to the impedance matching.
홍정기,김사덕,김순관,강대일,이명희,Hong, Jung-Ki,Kim, Sa-Dug,Kim, Soon-Kwan,Kang, Dai-Ill,Lee, Myeong-Hui 국립문화재연구소 2001 保存科學硏究 Vol.22 No.-
The facilities of exhibition and collection for cultural properties is affected by environmental pollution. In order to accumulate a store of basic data, we was investigated eight points(three points at exhibition room and five points at collection room) at four institutes, from December 2000 to March 2001.As a result of investigation, the temperature of A-Exhibition room measured low because of don’t moved HVAC(Heating, Ventilation and Air-Conditioning) System, B Exhibition room is dry for the effect of air-conditioner and the air pollutants concentration of C-Exhibition room is high for the kind of an exhibition room. The air-condition was varied within the open period. The air pollutants concentration of A-Collection room is measured high because the air-pollutants is generated in a new buildings and the air pollutants concentration of C-1 & C-2-Collection room is high for the kind of an collection room. It is necessary to ventilate sufficiently.
FR-4 composite 기판을 이용한 microstrip 전송선의 광대역 전송 특성 해석
홍정기,김영국,이해영 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.2
We analyzed wideband propagation characteristics of a microstrip transmission line based on FR-4 composite substrate using the wideband complex dielectric constant model and the phenomenological loss equivalence method. The loss calculated by constant relative permittivity and loss tangent is greatly overestimatd compared to that calculated by the frequency-dependent complex relative permittivity. This wideband analysis can be helpful to characterize high-speed and high-density transmission lines associated with the wideband dielectric characteristics and shows that the FR-4 composite substrate has high potential of high frequency circuit applications in terms o fthe propagation loss.
교수ㆍ학습에서 일어나는 의사소통 불일치 현상의 이론적 고찰
홍정기 한국교육과정평가원 2006 교육과정평가연구 Vol.9 No.1
This study investigates the communication discord between the teacher and the student in teaching and learning. In a traditional sense, communication between the teacher and the student was led by the teacher and the research concern was also on the teacher. But the focus of research has been shifted from the teacher to the learner who structures knowledge through teaching and learning. Transparent communication between the teacher and the student is necessary and is preferred by superficial observers. However, it is not enough to activate the true process of teaching and learning toward a new goal. Discord of communication between the teacher and the student in the teaching-learning situation is inevitable and a natural phenomenon. After a successful class, communication discord changes into communication accord. And a temporary communication accord is achieved. However, there may be another discord of communication between the teacher and the student before the next visible goal(end-in-view). That is, discord and accord of communication between the teacher and the student is repeated continuously. Therefore, teachers should design instructions focusing on the ways to transform discorded phenomena to accorded ones of communication about instructional objectives before teaching and learning activities occur. 본 연구는 교수·학습에서 일어나는 교사와 학생 간 의사소통의 불일치 현상에 대하여 고찰하였다. 전통적인 의미에서의 교사와 학생 간의 의사소통은 주로 교사 위주로 전개되었고 연구의 관심도 주로 교사였다. 하지만 점차 연구의 중심이 교수·학습을 통해 지식을 구성하는 학습자 중심으로 변화되어 가고 있다. 교사와 학생 간의 투명한 의사소통은 피상적인 수업 관찰자들이 선호하는 형식적이고 표면적인 수업의 전개를 위해서는 필요하지만, 새로운 목표를 향해 배우고 가르치는 교육 본질을 촉발할 에너지를 갖게 하지는 못한다. 교수·학습에서 교사와 학생 간 의사소통의 불일치는 필연적이고 자연스러운 현상이다. 의사소통의 불일치에서 일치로 변화되는 과정이 곧 성공적인 수업의 과정이고, 그러한 과정을 거친 후에는 일시적인 의사소통의 일치가 이루어진다. 하지만 이러한 정점에서 교사와 학생은 또 다시 다음의 가시 목표 앞에서 의사소통의 불일치가 일어난다. 즉 교사와 학생 간 의사소통의 불일치, 일치는 반복을 거듭한다. 따라서 교사는 교수·학습 활동에 앞서 수업 목표에 대한 학생들과의 의사소통 불일치 현상을 일치로 변화시키는 방법에 초점을 맞추어 수업 설계를 하여야 한다.