• Proceedings of the KSME Conference
• /
• 2005.11a
• /
• pp.184.1-184.1
• /
• 2005

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 1999.05a
• /
• pp.205-209
• /
• 1999

일반화된 지수생존모형(generalized exponential survival model)을 고려하여 이 모형의 모수를 추정하는 수정된 FS(modified Fisher scoring)방법을 제안한다. 이를 위해 우도방정식(likelihood equation)을 유도하고 초기추정치 (initial estimate)를 포함한 추정알고리즘(estimating algorithm)을 개발한다.

• Construction Engineering and Management
• /
• v.12 no.2
• /
• pp.17-22
• /
• 2011

남북 쌍방의 정치 협상이나 현황에 의미를 두지 말고 제 3 세계 주관사를 초청하여 서울 신의주 간 고속도로 민자 사업을 계획, 시공 및 관리하자는 주장은 이상에 불과할 수 있다. 남북 간 정경 분리 원칙을 내세우지만 간단한 미풍에도 흔들리고 있는 것이 개성공단의 현실이다. 필자는 거창한 통일 관련 학자는 아니지만 도로를 사랑하는 사람으로 도로인에 남북 화합의 지휘자가 되라고 권한다. 통상 사업 초기, 기획의 미비로 드는 추가 비용을 예방비용, 평가비용, 실패비용으로 구성할 수 있는데 대기업들은 예방비용에 미리 투자함으로써 품질은 높이고 비용은 줄이는 전략을 구사하고 있다. 대북 인프라 사업은 예방비용에 투자하는 것과 같다. 북한에 투자하는 SOC 사업은 비용은 파악하기 쉬운 반면, 그것이 가지고 올 이익은 장기적이고, 위험도가 크며, 또한 편익을 정량화하는 것이 어려운 특성이 있어 반대 여론이 높은 것이 사실이다. 그러나 조건 없는 남북 경협을 주장하는 것이 아닌 이상 남북 양 정부 이익을 창출할 수 있는 제 3자 방식의 민자를 통한 도로 사업은 현재 논의되고 있는 어떠한 SOC 사업보다 타당성이 있다. 도로 건설 불가론이란 거대 여론앞에 풍전등화의 두려움에 떨고 있는 건설인들에게 북한 도로 시장이라는 커다란 선물 보따리를 정부가 앞장 서 풀어주길 기대한다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.8 s.251
• /
• pp.897-905
• /
• 2006

This study considers an experimental design of disturbance compensation control to improve stabilization performance of main battle tanks. An adaptive non-parametric design technique based on the Filtered-x Least Mean Square(FXLMS) algorithm is applied in the consideration of model uncertainties. The optimal compensator is designed by two-step design procedures: determination of frequency response function of the disturbance compensator which can cancel the disturbance of series of single harmonics by using the FXLMS algorithm and determination of the compensator polynomial which can fit the frequency response function obtained in the first step optimally by using a curve fitting technique. The disturbance compensator is applied to a simple experimental gun-torsion bar-motor system which simulates gun driving servo-system. Along with experimental results, the feasibility of the proposed technique is illustrated. Experimental results demonstrate that the proposed control reduces the standard deviation of stabilization error to 47.6% that by feedback control alone. The directional properties of the FXLMS Algorithm such as the direction of convergence and its convergence speed are also verified experimentally.

• Journal of the Korean Geographical Society
• /
• v.38 no.1
• /
• pp.127-140
• /
• 2003

This study attempts to summarize the progress of Journalistic Cartography and to investigate the quantitative growth and the transition of the forms and contents of the media maps in Korean newspapers. And this study examines the characteristics of media maps with the technological development. The results of this study are summarized as follows. First, 'Jigujeondo' in Hanseongsunbo in 1880s is the first media map in Korea. Secondly, the number of the media maps in Korean newspapers is influenced by the political and economic environments. As the time goes, the contents of the media maps have been raried. Thirdly, the representation of the media maps has their own special characteristics according to the technological developments from the handwriting to CTS.

• Asia Marketing Journal
• /
• v.11 no.1
• /
• pp.29-38
• /
• 2009

Estimating the Bass diffusion model often creates a time-interval bias, which leads the OLS approach to overestimate sales at early stages and underestimate sales after the peak. Further, a specification error from omitted variables might raise serial correlations among residuals when marketing actions are not incorporated into the diffusion model. Autocorrelated disturbances may yield unbiased but inefficient estimation, and therefore invalid inference results. This phenomenon warrants a modified approach to estimating the Bass diffusion model. In this paper, the authors propose a modified Bass diffusion model handling autocorrelated disturbances. To validate the new approach, authors applied the method on two different data-sets: CT Scanners in the U.S, and FPD TV sales in Korea. The results showed improved model fit and the validity of the proposed model.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.40 no.4
• /
• pp.268-281
• /
• 2004

A study was carried out in order to estimate the deformation of the pound net according to the current by the model test in the circulating water channel. The tension of the frame rope and the variation of net shape were measured to investigate the deforming of the model pound net in the flow. The results are obtained as follows; 1. The experimental equation between tensions (R) of the frame rope and velocity (ν)was found to be R=$19.58v^{1.98}$($r^2$=0.98) in case of the upperward flow with fish court net and R=$26.90v^{1.72}$($r^2$=0.95)at the upperward flow with bag net according to the velocity from 0.0m/s to 0.6m/s, respectively. 2. As the variation of flow speed inside of the model net was gradually decreased according as which is passed through netting panels, in case of the upperward flow with fish court net, the flow speed was about 70% of initial flow speed at 0.1m/s, 60% at 0.2m/s, 50% at 0.3m/s and 40% 0.4~0.6m/s at the measurement point(h) inside of the first bag net, respectively. In case of the upperward flow with bag net, as the flow speed was steeply decreased according as which if passed through the second bag net, it was 30~60% of the initial flow speed and was 20~30% inside of the first bag net and was about 10~20% inside of the inclined passage net. 3. In case of the upperward flow with fish court net, the variation of deformed angle of fish court net was from 0$^{\circ}$ to 70$^{\circ}$and that of inclined passage net was from 0$^{\circ}$ to 63$^{\circ}$and that of the second bag net was from 0$^{\circ}$ to 47$^{\circ}$ . 4. In case of the upperward flow with fish court net, the variation of deformed angle of the second bag net was changed from 0$^{\circ}$ to 70$^{\circ}$and that of the inclined passage net was from 0$^{\circ}$ to 55$^{\circ}$ and that of the fish court net was from 0$^{\circ}$ to 50$^{\circ}$. The depth ratio of the first bag net was changed from 0% to 35% and that of the second bag net was from 0% to 20% and that of the inclined passage net was from 0% to 35%. In the flow speed 0.5m/s, the inclined passage net was raised up to the entry of the bag net and then prevented it more over 90%. 5. To be increased the opening volume of pound net, it needs to attach the added weight outside of the fish court net, inclined passage net and bag net. At the same time, it needs to adjust the tension of the twine for maintenance of the shape.

• Korean Journal of Remote Sensing
• /
• v.36 no.3
• /
• pp.487-501
• /
• 2020

As a viable option for retrieval of LST (Land Surface Temperature), this paper presents a DNN (Deep Neural Network) based approach using 148 Landsat 8 images for South Korea. Because the brightness temperature and emissivity for the band 10 (approx. 11-㎛ wavelength) of Landsat 8 are derived by combining physics-based equations and empirical coefficients, they include uncertainties according to regional conditions such as meteorology, climate, topography, and vegetation. To overcome this, we used several land surface variables such as NDVI (Normalized Difference Vegetation Index), land cover types, topographic factors (elevation, slope, aspect, and ruggedness) as well as the T₀ calculated from the brightness temperature and emissivity. We optimized four seasonal DNN models using the input variables and in-situ observations from ASOS (Automated Synoptic Observing System) to retrieve the LST, which is an advanced approach when compared with the existing method of the bias correction using a linear equation. The validation statistics from the 1,728 matchups during 2013-2019 showed a good performance of the CC=0.910~0.917 and RMSE=3.245~3.365℃, especially for spring and fall. Also, our DNN models produced a stable LST for all types of land cover. A future work using big data from Landsat 5/7/8 with additional land surface variables will be necessary for a more reliable retrieval of LST for high-resolution satellite images.

• Journal of Plant Biotechnology
• /
• v.36 no.1
• /
• pp.1-6
• /
• 2009

A study was conducted to investigate in vitro micro propagation of four potato cultivars of Daese, Jasim, Chubaek and Haryeng in MS medium and PM medium (a medium containing half concentration of $NH_4NO_3$ and $KNO_3$, two fold concentration of $CaCl_2$ as compared to MS medium). During $1{\sim}2$ weeks of culture, Daese and Jasim showed better shoot elongation on the solid MS medium than Chubaek and Haryeng whereas Chubaek and Haryeng did better shoot elongation on the solid PM medium. But no difference was observed after 4 weeks of culture. As compared to shoot elongation on the solid medium, it was delayed at early stage of culture in the liquid medium without shaking. Shoot formation ratio of potato (above 4 cm of shoot length) began to increase significantly after 1 week of culture and kept on increasing until 4 weeks. The four cultivars showed the different patterns of shoot growth in bioreactor. The PM medium with a quarter salt strength was effective for the regeneration of axillary buds as well as shoot elongation of Jasim and Chubaek. Daese showed vigorous regeneration of axillary buds in the PM medium with a half salt strength. On the other hand, Haryeng showed slower growth than the other three cultivars.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.14 no.2
• /
• pp.53-62
• /
• 2012

Demand for high resolution weather data grows in the agriculture and forestry fields. Local Analysis and Prediction System (LAPS) can be used to analyze the local weather at high spatial and temporal resolution, utilizing the data from various sources including numerical weather prediction models, wind or temperature profilers, Automated Weather Station (AWS) networks, radars, and satellites. LAPS has been set to analyze weather elements such as air temperature, relative humidity, wind speed, and wind direction every hour at the spatial resolution of $100m{\times}100m$ for Gyeonggi-do on near real-time basis. The AWS data were revised by adding the agricultural field AWS data (33 stations) in addition to the KMA data. The analysis periods were from 1 to 31 August 2009 and from 15 to 21 February 2010. The comparison of the LAPS output showed the smaller errors when using the agricultural AWS observation data together with the KMA data as its input data than using only either the agricultural or KMA AWS data. The accuracy of the current system needs improvement by further optimization of analyzing options of the system. However, the system is highly applicable to various fields in agriculture and forestry because it can provide site specific data with reasonable time intervals.