• 컴퓨터교육학회논문지
• /
• 제7권1호
• /
• pp.151-165
• /
• 2004

본 연구의 목적은 군집 분석(Cluster Analysis) 및 사회연결망 분석 기법의 일종인 커뮤니티(Community)기법을 활용한 직무 분석 사례를 소개하고 그 결과를 음미해 보는데 있다. 이러한 작업을 통해 기존에 활용되던 직무분석 기법을 보완할 수 있는 계량적 방법론을 구안해냄으로써 궁극적으로 역량기반 커리큘럼의 개발 및 교수체제 설계 시 보다 분석적, 과학적인 준거 자료를 확보할 수 있을 것으로 기대하였다. 본 연구를 위한 직무분석 자료는 국내 대규모 제조업체인 S사에서 인터뷰 및 설문을 통해 수집되었다. 이 자료를 활용하여 실시된 군집 분석의 결과 직무들 간의 유사성에 대한 군집 분석 결과는 공식적인 직무 분류체계와 상당한 차이를 보이고 있음이 판명되었다. 이는 조사된 모든 측면에서 일관되게 확인되었으며, 각 측면별로 다소 상이한 클러스터링 패턴을 보이고 있었다. 군집 분석에 이어 직무들 간의 상호 연결관계 네트워크에 대한 사회연결망분석이 실시되었는데, 그 결과 명확한 중심-주변 구조와 함께 클러스터링 구조를 갖고 있음을 확인할 수 있는데, 이는 공식적인 직무분류체계에서 예상할 수 있는 것과도 다르고 또한 직무 간 내용적 유사성 구조와도 차이가 있는 독특한 패턴을 보이고 있음을 보이고 있는 결과였다. 이러한 연구 결과를 통해서 직무분석을 위한 새로운 분석 알고리즘으로서 군질 분석 및 커뮤니티 분석 기법의 유용성이 확인되었다. 나아가 향후 교육체계 설계를 위해 선행되는 직무분석 시 유의할 점들을 논의하였다.

• 컴퓨터교육학회논문지
• /
• 제23권2호
• /
• pp.53-64
• /
• 2020

동영상 강의 중심의 온라인 학습 형태가 보편화 되고 지속적으로 증가됨에 따라 다양한 교육방법을 적용한 동영상 기반 학습 환경도 학습 효과성을 높이기 위해 변화, 발전하고 있다. 온라인 학습 환경에서의 교육 효과성 측정을 위해 학습자 로그 데이터가 대두되었으며, 학습자 맞춤형 학습 처방을 위해 로그 데이터의 다양한 분석 방법이 중요하다. 이를 위해 본 연구에서는 동영상 기반 학습 환경에서의 학습자 행동 데이터 분석, 머신러닝 기법에 따른 학업성취 예측을 실험을 통해 분석하였다. 분석 결과 각 모델에서 공통적으로 동영상 탐색과 코멘트 작성과 같은 상호작용 행동, 학습자 주도적 학습 행동이 학업성취를 예측하였다. 연구 결과를 토대로 동영상 학습 환경 설계에 있어 시사점을 제공하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.1964-1969
• /
• 2010

최근 건설시장 규모가 확대되고 교통산업이 발전하면서 지하철 및 터널 등과 같은 개착형 Box 혹은 Shield형 터널 구조물 등 지하구조물의 건설이 다양화되고, 그 수요도 점차 급증하고 있는 실정이다. 그러나 주로 지하에 건설되는 콘크리트 구조물은 시공시 신축이음 및 시공 조인트 등과 같은 다양한 형태의 조인트 발생과 구조물의 수축팽창에 따른 거동, 부동침하, 과다하중, 진동발생에 의한 균열로 인하여 누수가 발생되고 있다. 이에 다양한 방수공법 및 재료들이 현장에 적용되고는 있지만 지하철도, 지하철 등과 같은 진동 및 구조물의 거동이 상시적으로 발생되는 환경조건에서는 방수층의 성능이 저하되어 균열, 침식, 들뜸 등으로 물이 확산되어 재누수가 되는 악순환을 겪고 있는 실정이다. 따라서 본 연구에서는 진동 및 구조물의 거동에 대응 가능한 점착 유연형 복합방수공법을 대상으로 구조물의 거동 대응성 시험을 평가하고, 거동 및 진동이 상시적으로 발생되는 지하철, 터널 등을 대상으로 실제 현장에 적용 후 사례를 통해 구조물 거동에 대응 가능한 방수기술을 검토하였다. 이러한 거동 대응 특성을 검토한 결과 방수재가 기건 및 수중환경에서도 재료의 유연성과 부착성을 유지하여 물의 침투를 방지하고, 거동폭 $5.0mm({\pm}0.5)$ 범위에서도 거동에 대응 가능함을 알 수 있었다.

• 환경영향평가
• /
• 제15권2호
• /
• pp.93-100
• /
• 2006

In general, the verification to prediction formula in a national road and the main street of a town has been used recklessly in Korea. Therefore we investigated the validity of an existing prediction formula (NIER(87, 99), TR-Noise, KLC(2002)) with correction relationship which was based on both the prediction formular from apartment complex in the field and height 1.5m from the surface level. On the results of measuring the noise level form an isolated distance, the noise level showed that it was 4.5~5.5dB(A) by reason of becoming 2 folder far from a source. From the distribution of noise level measured by the apartment floors, the measurement point (1st floor) was 58.7~71.4dB(A) at its lowest level and the middle floors (3, 5, 7 and 10) were the highest distribution of noise level. From the analysis results on the application validity to an existing prediction formular (NIER(87, 99), TR-Noise, KLC(2002)) in the height 1.5m, the correction coefficients were 0.95~0.96 and the measured values were reasonably close to the predicted values, indicating the validity and adequacy of the predicted models. KLC(2002) model was found accurate within 3dB(A) with 36 data out of the total 42 data, showing the most accuracy among the predict models. However, the developed models have to improve the accuracy with a various of factors.

• 신재생에너지
• /
• 제9권2호
• /
• pp.15-22
• /
• 2013

The solar energy are an infinite source of energy and a clean energy without secondary pollution. The global solar energy reaching the earth's surface can be calculated easily according to the change of latitude, altitude, and sloped surface depending on the amount of the actual state of the atmosphere and clouds. The high-resolution solar-meteorological resource map with 1km resolution was developed in 2011 based on GWNU (Gangneung-Wonju National University) solar radiation model with complex terrain. The very high resolution solar energy map can be calculated and analyzed in Seoul and Eunpyung with topological effect using by 1km solar-meteorological resources map, respectively. Seoul DEM (Digital Elevation Model) have 10m resolution from NGII (National Geographic Information Institute) and Eunpyeong new town DSM (Digital Surface Model) have 1m spatial resolution from lidar observations. The solar energy have small differences according to the local mountainous terrain and residential area. The maximum bias have up to 20% and 16% in Seoul and Eunpyung new town, respectively. Small differences are that limited area with resolutions. As a result, the solar energy can calculate precisely using solar radiation model with topological effect by digital elevation data and its results can be used as the basis data for the photovoltaic and solar thermal generation.

• 환경위생공학
• /
• 제21권3호
• /
• pp.15-26
• /
• 2006

As traffic in city-centre around the world continues to increase, so levels of atmospheric pollutants continue to rise. High concentrations of NOx can have negative effects on human health, and we must find new ways to reduce their levels in the air we breathe. Nitrogen oxide gas (NOx), consisting of nitrogen monoxide (NO) and nitrogen dioxide $(NO_2)$ produced using $O_3$ oxidation, at a low concentration corresponding to that on roads as a result of exhaust from automobiles, was carried out to evaluate the removal characteristics of NOx through a laboratory-scale biofilter packed with soil as a packing material. A mixture media (yellow soil (30%): soil (40%): compost (10%): a used briquet (20%)) was applied. After about 1day of operation, the removal efficiency for $NO_2$ in all experiments with a constant condition ($25^{\circ}C$ and water humidity (60%)) was over 98%. The retention times of the section between phase I and phase II for formation and reduction of $NO_3$ NO and $NO_2$ on the initial $NO_3$ concentration was 50min $(O_3:195\;ppb),\;55min\;(O_3:925\;ppb),\;65min\;(O_3:1743\;ppb),\;70min\;(O_3:2616\;ppb),\;75min\;(O_3:3500\;ppb)$, respectively The soil biofilter system is a unique technology that purifies urban air by utilizing the natural processes that take place in the soil. Although some of the processes are quite complex, they can broadly be summarized as adsorption onto soil particles, dissolution into soil pore water, and biochemical.

• 천문학회보
• /
• 제35권1호
• /
• pp.30.2-30.2
• /
• 2010

Numerous operational anomalies and satellite failures have been reported since the beginnings of the "space age". Space weather effects on modern spacecraft systems have been emphasized more and more as increasing their complexity and capability. Energetic particles potentially can destroy and degrade electronic components in satellites. We analyzed the geostationary (GEO) satellite anomalies during 1997-2009 to search possible influences of space weather on the satellite anomalies like power problem, control processor problem, attitude control problem, etc. For this we use particle data from GOES and LANL satellites to investigate space weather effects on the GEO satellites' anomalies depending on Kp index, local time, seasonal variation, and high-energy electron contribution. As results, we obtained following results: (1) there is a good correlation between geomagnetic index(Kp) and anomaly occurrences of the GEO satellite; (2) especially during the solar minimum, occurrence of the satellite anomalies are related to electron flux increase due to high speed solar wind; (3) satellite anomalies occurred more preferentially in the midnight and dawn sector than noon and dusk sector; (4) and the anomalies occurred twice more in Spring and Fall than Summer and Winter; (5) the electron with the lowest energy channel (50-75keV) has the highest correlation (cc=0.758) with the anomalies. High association between the anomalies and the low energy electrons could be understand by the facts that electron fluxes in the spring and fall are stronger than those in the summer and winter, and low-energy electron flux is more concentrated in the dawn sector where the GEO satellite anomalies occurred more frequently than high-energy electron flux. While we could not identify what cause such local time dependences, our results shows that low-energy electrons (~100keV) could be main source of the satellite anomaly, which should be carefully taken into account of operating satellites.

• 한국해양공학회지
• /
• 제27권4호
• /
• pp.76-82
• /
• 2013

Motion reduction of an offshore structure at resonant frequency is essential for avoiding critical damage to the topside and mooring system. A damping plate has a distinct advantage in reducing the motion of a floating structure by increasing the added mass and the damping coefficient. In this study, the heave motion responses of a circular cylinder with an impermeable and a permeable damping plate attached at the bottom of the cylinder were investigated thru a model test. The viscous damping coefficients for various combinations of porosity were obtained from a free-decay test by determining the ratio between any pair of successive amplitudes. Maximum energy dissipation occurred at a porous plate with a porosity P = 0.1008. Experimental results for regular and irregular waves were compared with an analytical solution by Cho (2011). The measured heave RAO and spectrum reasonably followed the trends of the predicted values. A significant motion reduction at resonant frequency was pronounced and the heaving-motion energy calculated by the integration of the area under the heave motion spectrum was reduced by more than 75% by the damping plate. However, additional energy dissipation by eddies of strong vorticity and flow separation inside a porous damping plate was not found in the present experiments.

• 한국전자파학회논문지
• /
• 제21권9호
• /
• pp.940-946
• /
• 2010

본 논문에서는 휴대용 컴퓨터 내 WWAN 대역에서 동작 가능한 평판 회로 기판형 내장형 안테나를 제안하였다. 제안된 안테나는 GSM850/900 대역에서의 안테나 특성을 개선하기 위하여 평판 회로 기판 위에 인쇄되어 있는 기판을 제거한 후 패턴의 일부를 금속 구조체로 대체하였다. 제안된 안테나는 가로 74 mm, 세로 11 mm, 높이 0.5 mm의 크기로 금속 구조체를 사용하지 않은 평판 회로 기판형 안테나와 비교하였을 때 유사한 크기를 가졌음에도 불구하고 해당 주파수 대역에서 약 42 %의 대역폭 증가 특성을 보였다. 금속 구조체를 사용한 GSM850/900 대역에서 측정된 방사 이득의 경우 -4.45~-2.29 dBi로 금속 구조체를 사용하지 않은 안테나보다 높은 방사 이득 특성을 보였다.

• 한국환경보건학회지
• /
• 제32권2호
• /
• pp.118-125
• /
• 2006

The road traffic noise has been increasing broader effects on urban areas as well as rural areas because of rapidly increasing traffic volume and newly-constructed roads. 10 sites in building development areas were selected and the noise levels were measured by the apartment floors and by the various block plans of apartment complex. The results showed that the highest traffic noise level was obtained at the 5 and 7 floors on the apartment floors. On the basis of 7 floor with the highest level, the correction coefficient obtained from noise reduction by each floor and measurement point was -5.54 dB(A)(1st floors), -0.96 dB(A)(3rd floors), -0.38 dB(A)(5th floors), 0.00 dB(A)(7th floors), -1.98 dB(A)(l0th floors), -3.10 dB(A)(13th floors), -3.45 dB(A)(15th floors). The level of road traffic noise in the arrangement construction of right angle was about 3.0 dB(A) at N-4 point and 2.1 dB(A) at N-6 point lower than that of a plan figure, respectively. The results suggested that application of correction coefficient obtained by the apartment floor and by the arrangement construction can be improved in road traffic noise.