• 한국정보전자통신기술학회논문지
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• 제13권6호
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• pp.590-596
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• 2020

상용전력망과 계통연계가 어려운 도서지역에서는 독립적인 마이크로그리드로 생산된 에너지를 효율적으로 관리할 수 있는 방법을 찾는 것은 매우 중요한 일이다. 본 논문에서는 태양광과 풍력의 하이브리드 모델을 적용한 소규모 마이크로그리드에서 생산된 전력을 전력계측기와 수집된 데이터의 응답속도 테스트를 거쳐 P2P전력거래를 위한 프로슈머관리시스템을 구현하였다. 마이크로그리드 프로슈머 관리시스템의 전력망은 Mesh구조로 이루어져 있으며 P2P전력거래는 3곳의 독립적으로 구축된 off-grid 사이트에서 전력계측기와 DC전력전송기를 이용하여 테스트하였고, 이때 전력계측기의 측정값은 전압(평균값) : 380V + 0.9V, 전류(평균값) : + 0.01A, 전력 : 1000W ( - 1W)로 오차 허용범위인 ±1%이내로 나타나 그 유의성을 확인하였다. 실시간으로 50개의 데이터를 동시 전송하여 메인화면 0.32초, 일 발전량 2.61초, 누적발전량 2.77초, 전력거래 0.11초 등의 응답속도가 나타나 서버의 안정화를 확인하였다. 따라서 본 시스템은 한국전력의 중계 없이 독립적인 망으로 활용될 수 있는 P2P 전력거래시스템으로서 그 타당성이 입증되었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.485-490
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• 1999

Wind vector information over the ocean is currently obtained using multiple beam scatterometer data. The scatterometers on ERS-1/2 generate wind vector information with a spatial resolution of 50km and accuracies of $\pm$2m/s in wind speed and $\pm$20$^{\circ}$ in wind direction. Synthetic aperture radar (SAR) data over the ocean have the potential of providing wind vector information independent of weather conditions with finer resolution. Finer resolution wind vector information can often be useful particularly in coastal regions where the scatterometer wind information is often corrupted because of the lower resolution system characteristics which is often contaminated by the signal returns from the coastal areas or ice in the case of arctic environments. In this paper we tested CMOD_4 and CMOD_IFR2 algorithms for extracting the wind vector from SAR data. These algorithms require precise estimation of normalized radar cross-section and wind direction from the SAR data and the local incidence angle. The CMOD series algorithms were developed for the C-band, VV-Polarized SAR data, typically for the ERS SAR data. Since RADARSAT operates at the same C-band but with HH-Polarization, the CMOD series algorithms should not be used directly. As a preliminary approach of resolving with this problem, we applied the polarization ratio between the HH and VV polarizations in the wind vectors estimation. Two test areas, one in front of Inchon and several sites around Jeju island were selected and investigated for wind vector estimation. The new results were compared with the wind vectors obtained from CMOD algorithms. The wind vector results agree well with the observed wind speed data. However the estimation of wind direction agree with the observed wind direction only when the wind speed is greater than approximately 3.0m/s.

• 한국조경학회지
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• 제35권1호
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• pp.48-58
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• 2007

The purpose of this study was not only to clearly examine the features of the scenery and visual elements of Oreum (parasitic cones) but also to investigate primary factors in landscape preferences for these cones. This study further attempted to gain basic information for examining the preservation of Oreum in regards to the influence of scenery on the general public. A Multiple Regression Analysis was used for this study for which the independent variable was the area ratio of the fore-, mid-, and background of the view under the feature element and the structure of the scenery at the Oreum. The dependent variables were the preference value, the number of summits, and the highest altitude of the Oreum. All but the highest inclination were positive variables. The area ratio of the Oreum was found to be the most important variable. The area of sky and the area of the distant scenery were shown to be positive explanation variables, while the area to the fore of the view and the area to the middle of the view were shown as negative explanation variable. In the preference for Oreum scenery, which has a high visibility and is clearly outlined against the skyline, it was found that as the hindrance element of visibility near to a visual point or the area ratio increased, the preference for the Oreum scenery decreased.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.906-913
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• 2004

A culture-independent molecular phylogenetic survey was carried out on the bacterial community in cold-seep sediment at Edison Seamount, south of Lihir Island, Papua New Guinea. Small-subunit rRNA genes were amplified directly from the sediment DNA by PCR and cloned. The majority of the cloned 16S rRNA gene sequences were most closely related to as-yet-uncultivated microorganisms found in deep-sea sediments, and were primarily affiliated with one of four groups: the $\gamma$-, $\delta$-, and $\epsilon$-subdivisions of Proteobacteria, and Cytophaga-Flavobacterium-Bacteroides. We did not recover any sequences related to cyanobacteria, prochlorophytes, and $\alpha$-Proteobacteria, which are known to occur in great abundance within the surface mixed layer of the Atlantic and Pacific Oceans. The majority of the cloned $\gamma$-and $\epsilon$-Proteobacterial sequences were closely related to chemoautotrophic sulfur-oxidizing symbionts of marine benthic fauna, and the $\delta$-Proteobacterial sequences to sulfate- and sulfur-reducing bacteria, indicating that they might play an important role in chemoautotrophic primary production and the sulfur cycle in the cold-seep area. There results demonstrate the high diversity of the bacterial community in the cold-seep sediment, and substantially expand knowledge of the extent of bacterial diversity in this formidable and unique habitat.

• Structural Engineering and Mechanics
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• 제23권4호
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• pp.409-430
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• 2006

The aim of this study is to investigate the reliability of strong motion records processed by causal and acausal Butterworth filters in comparison to the results obtained from a synthetic accelerogram. For this purpose, the fault parallel component of the Bolu record of the Duzce earthquake is modeled with a sum of exponentially damped sinusoidal components. Noise-free velocities and displacements are then obtained by analytically integrating the synthetic acceleration model. The analytical velocity and displacement signals are used as a standard with which to judge the validity of the signals obtained by filtering with causal and acausal filters and numerically integrating the acceleration model. The results show that the acausal filters are clearly preferable to the causal filters due to the fact that the response spectra obtained from the acausal filters match the spectra obtained from the simulated accelerogram better than that obtained by causal filters. The response spectra are independent from the order of the filters and from the method of integration (whether analytical integration after a spline fit to the synthetic accelerogram or the trapezoidal rule). The response spectra are sensitive to the chosen corner frequency of both the causal and the acausal filters and also to the inclusion of the pads. Accurate prediction of the static residual displacement (SRD) is very important for structures traversing faults in the near-fault regions. The greatest adverse effect of the high pass filters is their removal of the SRD. However, the noise-free displacements obtained by double integrating the synthetic accelerogram analytically preserve the SRD. It is thus apparent that conventional high pass filters should not be used for processing near-fault strong-motion records although they can be reliably used for far-fault records if applied acausally. The ground motion parameters such as ARIAS intensity, HUSID plots, Housner spectral intensity and the duration of strong-motion are found to be insensitive to the causality of filters.

• 한국안전학회지
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• 제33권5호
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• pp.101-108
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• 2018

This study was carried out to obtain baseline data on the causes of industrial accidents and their prevention by investigating structural models between the Shipyard workers' egogram ego-states (CP: Critical Parent, NP: Nurturing Parent, A: Adult, FC: Free Child, AC: Adapted Child), safe and unsafe behaviors, and industrial accidents (frequency/severity). In order to achieve this goal, 378 workers from 3 locations of major corporations in Geojedo Island and Ulsan took a questionnaire, which was then analyzed with a structural equation model using the SPSS 23.0 and AMOS 24 statistics package, and the main results of the study are as follows. First, NP and A's ego-states had a positive influence on safe behavior, AC's ego-state had a negative influence on safe behavior, and A's ego-state had the largest influence on safe behavior. Second, CP and AC's ego-states had a positive influence on unsafe behavior, and A's ego-state had a negative influence on unsafe behavior. AC's ego-state had the largest influence on unsafe behavior. Third, safe behavior did not have a significant influence on industrial accidents. However, unsafe behavior had a positive influence on industrial accident frequency and industrial accident severity, both sub-factors of industrial accidents. This study, despite its limitations, such as sampling limitations, has the following significance. First, this study verified that ego-state, a psychological characteristic, is an important factor for predicting unsafe behavior that induces industrial accidents. Second, in order to reduce industrial accidents, there is a need to stimulate the A ego-states, and promote continuous safety management and safety education to neutralize the AC ego-state. Third, previous studies were limited in the area of practical methods for reducing unsafe behaviors, but this study presents practical methods for reducing unsafe behaviors by verifying the structural relationship between safe/unsafe behaviors and industrial accidents by selecting ego-gram ego-states, variable personality theory, as an independent variable.

• 한국응용곤충학회지
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• 제40권2호
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• pp.105-109
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• 2001

귤응애의 예찰방법을 개발하기 위하여 제주지역의 온주밀감원에서 귤응애 분산형태에 대해 2개년(1999~2000년)에 걸쳐 잎 표본에 대하여 각 조사일에 평균밀도를 조사하였다. Taylor's power law와 Iwao's patchiness regression을 이용하여 분산지수를 비교하였으며, 잎 표본 조사에서는 일반적으로 Taylor's power law가 Iwao's patchiness regression보다 평균-분산 관계를 더 잘 나타내었다. Taylor's power law의 기울기와 절편은 조사한 포장 간에 차이가 없었으며, 여기에서 얻어진 상수값을 이용하여 잎 표본 조사에 의한 귤응애 약 .성충에 대한 고정정확도수준에서의 표본조사법을 개발하였다. 이 조사법에 대해 resampling 기법을 이용하여 독립된 4개의 조사자료를 이용하여 분석한 결과 실질 고정정확도(D)값이 요구되는 D값보다 항상 낮았으며, 나무당 귤응애 밀도가 8마리 이상에서 필요한 조사 나무수는 18주보다 작았다.

• 대기
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• 제24권1호
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• pp.101-110
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• 2014

This study estimates and evaluates the daily January temperature from 2003 to 2012 with 30 m-resolution over South Korea, using a modified Parameter-elevation Regression on Independent Slopes Model (K-PRISM). Several factors in K-PRISM are also adjusted to 30 m grid spacing and daily time scales. The performance of K-PRISM is validated in terms of bias, root mean square error (RMSE), and correlation coefficient (Corr), and is then compared with that of inverse distance weighting (IDW) and hypsometric methods (HYPS). In estimating the temperature over Jeju island, K-PRISM has the lowest bias (-0.85) and RMSE (1.22), and the highest Corr (0.79) among the three methods. It captures the daily variation of observation, but tends to underestimate due to a high-discrepancy in mean altitudes between the observation stations and grid points of the 30 m topography. The temperature over South Korea derived from K-PRISM represents a detailed spatial pattern of the observed temperature, but generally tends to underestimate with a mean bias of -0.45. In bias terms, the estimation ability of K-PRISM differs between grid points, implying that care should be taken when dealing with poor skill area. The study results demonstrate that K-PRISM can reasonably estimate 30 m-resolution temperature over South Korea, and reflect topographically diverse signals with detailed structure features.

• Journal of Preventive Medicine and Public Health
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• 제9권1호
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• pp.31-37
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• 1976

This study was conducted for the purpose of obtaining basic information on the patterns of medical care expenditures, and identifying some determinants of medical care expenditures in the rural Korea. Nine guns were chosen from the eight provinces, excluding Cheju island. One gun in each province and two villages were selected from the each myon or ub within the selected guns. The total number of households was 1,789 and the sample size was 9,826 non-institutionalized people. Followings are the major findings of the study : 1) Medical care expenditures increase proportionally with age in terms of cost per patient, per episode of illness, per treated case, and per person. Averagely, it cost 2,756 won per patient, 2,614 won per spell of illness, 4,361 won per treated case, and 413 won per person. 2) Medical care expenditures increase proportionally with educational level of patients. College graduates spent the most, 4,726 won per patient, 5,987 won per treated case, and 670 won per person. 3) The male spent a little more than the female in terms of per patient, per episode, and per person. For example, a male spent 23 won more than a female. 4) Those who were suffering from illnesses longer than 1 year spent three times more than that had illnesses of less than 1 year duration. 5) The simple correlation coefficient between activity restriction and medical care expenditures was the highest among others, 0.491. The next was 0.294 between duration of illness and medical care expenditures. 6) Attempts are made to identify the explanatory variables in medical care expenditures. Thirty one per cent of the variances in tile expenditures can be accounted for by the selected 15 predictors. Those predictors belonged to clinical renditions, such as activity restriction, duration of illness, and nature of conditions, are proved to be the most potent independent variabes. Level of education and monthly family income are also significant in terms of beta coefficient. Further studies are called for to unreveal the determinants of medical expenditures.

• 대한병리학회지
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• 제52권6호
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• pp.386-395
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• 2018

Background: Previous studies on synchronous colorectal carcinoma (SCRC) have reported inconsistent results about its clinicopathologic and molecular features and prognostic significance. Methods: Forty-six patients with multiple advanced tumors (T2 or higher category) who did not receive neoadjuvant chemotherapy and/or radiotherapy and who are not associated with familial adenomatous polyposis were selected and 99 tumors from them were subjected to clinicopathologic and molecular analysis. Ninety-two cases of solitary colorectal carcinoma (CRC) were selected as a control considering the distributions of types of surgeries performed on patients with SCRC and T categories of individual tumors from SCRC. Results: SCRC with multiple advanced tumors was significantly associated with more frequent nodal metastasis (p=.003) and distant metastasis (p=.001) than solitary CRC. KRAS mutation, microsatellite instability, and CpG island methylator phenotype statuses were not different between SCRC and solitary CRC groups. In univariate survival analysis, overall and recurrence-free survival were significantly lower in patients with SCRC than in patients with solitary CRC, even after adjusting for the extensiveness of surgical procedure, adjuvant chemotherapy, or staging. Multivariate Cox regression analysis revealed that tumor multiplicity was an independent prognostic factor for overall survival (hazard ratio, 4.618; 95% confidence interval, 2.126 to 10.030; p<.001), but not for recurrence-free survival (p=.151). Conclusions: Findings suggested that multiplicity of advanced T category-tumors might be associated with an increased risk of nodal metastasis and a risk factor for poor survival, which raises a concern about the guideline of American Joint Committee on Cancer's tumor-node-metastasis staging that T staging of an index tumor determines T staging of SCRC.