• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권5호
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• pp.462-469
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• 2000

Positron Emission Tomography(PET) is a new diagnostic method that can create functional images of the distribution of positron emitting radionuclides, which when administered intravenously in the body, makes possible anatomical and functional analysis by quantity of biochemical and physiological process. After genetic and biochemical changes in initial stage, malignant tumor undergoes functional changes before undergoing anatomical changes. So, early diagnosis of malignant tumors by functional analysis with PET can be achieved, replacing traditional anatomical analysis, such as computed tomography(CT) and magnetic resonance image(MRI), etc. Similarly, PET can identify malignant tumor without confusion with scar and fibrosis in follow up check. In the Korea Cancer Center Hospital(KCCH) from October 1997 to September 1999, clinical study was performed in 79 cases that underwent 89 times PET evaluation with [18F]-Fluorodeoxyglucose for diagnosis of oral and maxillofacial tumors, and the data was analysed by Bayesian $2{\times}2$ Classification Table. The results were as follows : Evaluation for initial diagnosis with FDG-PET (P<0.005) 1. Agreement rate or accuracy rate is 88.9%. 2. Sensitivity is 95.2%, and specificity 66.7%. 3. Positive predictive rate is 90.9%, and negative predictive rate 80.0%. 4. In consideration of tumor stage, diagnostic rate in less than stage II was 90% and in greater than stage III 100%. 5. In consideration of tumor size, diagnostic rate in less than T2 was 92.3% and in greater than T3 100%. After primary treatment, evaluation for follow up check with FDG-PET (P < 0.001) 1. Agreement rate or accuracy rate is 85.4%. 2. Sensitivity is 87.5%, and specificity 82.4%. 3. Positive predictive rate is 87.5%, and negative predictive rate 82.4%. 4. In 24 recurred cases, 6 had distant metastasis, and 5 of them were diagnosed with FDG-PET, resulting in diagnostic rate of FDG-PET of 83.3%. From the above results, Positron Emission Tomography with [18F]- Fluorodeoxyglucose appears to be more sensitive and accurate for detecting the presence of oral and maxillofacial tumors, and has various clinical applications such as early diagnosis of tumor in initial and follow up check and detection of distant metastasis.

• 한국정보통신학회논문지
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• 제9권1호
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• pp.108-116
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• 2005

분산 멀티미디어 환경에서 교재 제시를 위한 미디어내${\cdot}$미디어간 동기화는 전송 데이터의 지연과 손실 및 미디어별 전송 특성 등과 같이 비동기 오차로 인해 미디어들간의 정확한 시간 관계성을 보장하기가 매우 어렵다. 미디어내 동기화는 표현률에 영향을 받기 때문에 네트워크 지연으로 인한 미디어 도착률이 비정상적일 때 지터 현상이 발생한다. 그리고 각각의 미디어 스트림에서 지터의 누적된 결과로 미디어간 스큐가 발생한다. 이런 현상은 원거리 교육에서 네트워크 지연으로 인해 학습자의 내용 인식에 혼란을 야기시키고, 송${\cdot}$수신측의 효율적인 상호 작용을 제공하지 못하고 있다. 따라서 본 논문에서는 미디어 또는 하나 이상의 미디어 사이에서 시간 관계성의 요구 사항을 유지함으로써 네트워크 지연으로 인한 문제점을 해결할 수 있다. 또한 표현률에 영향을 받는 미디어내 동기화 방법을 제안하고, 원격 교육을 위한 교재 제시 시스템을 구현하였다.

• 산업과 과학
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• 제1권2호
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• pp.9-16
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• 2022

본 연구는 이완음악감상이 입원한 정신질환자의 기분상태 및 자율신경계 즉 심박동수에 미치는 영향을 파악하고자 실험군 17명, 대조군 17명을 대상으로 시행한 무작위 대조군 전후설계이다. 수집된 자료는 SPSS V15.0으로 분석하였다. 기분상태와 자율신경계 즉 심박동수는 두 집단 간에 통계적으로 유의한 차이가 있어 이완음악감상의 효과를 객관적으로 검증하였다(<.05). 기분상태의 하위 영역 중 분노(>.39)와 혼돈(>.33)을 제외한 긴장(<.00), 우울(<.00), 활력(<.03), 피로(<.01)에서 유의한 차이가 있는 것으로 나타나 입원한 정신질환자에게 적용할 수 있는 효과적인 중재방법임을 입증하였다. 향후 장기적인 중재 연구개발 및 적용과 개인의 선호음악을 이용하여 기분변화와 자율신경계에 효과연구를 제언하고자 한다.

• Computers and Concrete
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• 제32권3호
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• pp.327-337
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• 2023

Concrete is the most widely used building material, with various types including high- and ultra-high-strength, reinforced, normal, and lightweight concretes. However, accurately predicting concrete properties is challenging due to the geotechnical design code's requirement for specific characteristics. To overcome this issue, researchers have turned to new technologies like machine learning to develop proper methodologies for concrete specification. In this study, we propose a highly accurate deep learning-based predictive model to investigate the compressive strength (UCS) of lightweight concrete with natural aggregates (pumice). Our model was implemented on a database containing 249 experimental records and revealed that water, cement, water-cement ratio, fine-coarse aggregate, aggregate substitution rate, fine aggregate replacement, and superplasticizer are the most influential covariates on UCS. To validate our model, we trained and tested it on random subsets of the database, and its performance was evaluated using a confusion matrix and receiver operating characteristic (ROC) overall accuracy. The proposed model was compared with widely known machine learning methods such as MLP, SVM, and DT classifiers to assess its capability. In addition, the model was tested on 25 laboratory UCS tests to evaluate its predictability. Our findings showed that the proposed model achieved the highest accuracy (accuracy=0.97, precision=0.97) and the lowest error rate with a high learning rate (R2=0.914), as confirmed by ROC (AUC=0.971), which is higher than other classifiers. Therefore, the proposed method demonstrates a high level of performance and capability for UCS predictions.

• 한국항만경제학회지
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• 제32권4호
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• pp.127-147
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• 2016

본 연구는 1997년 부두운영회사(TOC)제 도입 이후 적용과정에서 다수의 문제점이 노정되어 온 현행(2003~2014) TOC제 부두의 임대료 체계를 합리적으로 개선하기 위한 방안을 제시하는데 그 목적이 있다. 이에 따라 표준화, 단순화, 형평성 도모라는 세 가지 방향으로 임대료 체계를 개편하고자 하였다. 최종 개편대안은 재산가치와 정책요율인 무역항사용료가 반영된 임대료 산정 방식을 채택하였다. 왜냐하면 현행 임대료 체계의 가장 큰 문제점을 해소하면서 개편에 따른 혼란을 최소화할 수 있기 때문이다. 나아가 적정대안에 의해 재산정된 안벽임대료의 급격한 인상을 방지하기 위해 TOC제 부두별 개편안벽임대료가 기존 선석임대료와 동일하게 되는 개별 조정률을 도입하였다. 이는 임대인인 정부와 항만공사가 부두운영회사(TOC)의 임대료 부담을 경감하는 정책적 목적이 우선될 필요성이 높았기 때문이다. 본 연구는 임대재산의 재산가치를 반영함은 물론 단순하면서도 표준화된 새로운 TOC제 부두 임대료 체계를 마련했다는 데 큰 의의가 있다. 또한 정책요율(무역항 시설사용료)이 적용되는 야적장 통로 창고(상옥) 임대료를 동일한 기준으로 모든 부두에 적용시킴으로써 일정 부문 형평성을 확보한 것도 큰 성과로 평가할 수 있다. 다만 개별 조정률을 도입함에 따라 안벽임대료가 면적에 비례하여 부과되지 못해 형평성이 저해되는 한계점도 동시에 내포하고 있다. 향후 부두 운영 여건이 개선되는 정도에 따라 단계적으로 부두별 개별 조정률을 동일한 목표 조정률인 0.5 수준으로 현실화시켜야 할 것이다.

• 한국안전학회지
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• 제22권4호
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• pp.96-101
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• 2007

Usually pictograms embedded in safety signs are such final means to transmit hazard information that the importance of them cannot be emphasized too much. Nevertheless, in Korea, few people are interested in safety signs and their functions so that evaluation of safety signs are seldom committed nor safety signs draw workers' attention to fulfill their functions. Therefore this research aimed to standardize the procedure for developing safety signs in order not only to give practical help to industrial workers but to match them international standards, and to develop a few examples through the suggested standard procedure. As results, a procedure for developing industrial safety signs was developed by combining both ANSI Z535.3 and ISO 9186 with a special emphasis on action inducibility as the former emphasized as well as comprehensibility as the latter suggested. According to test results with undergraduate students as well as industrial workers on a few signs developed through the suggested procedure, action inducibility was higher whereas confusion rate was lower than expected on one hand, and it could be concluded that the procedure would supply results that can be satisfied on the other hand.

• 임상간호연구
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• 제20권3호
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• pp.406-416
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• 2014

Purpose: Screening of delirium using delirium assessment tools could promote delirium detection, however, there is lack of report about regular delirium assessment in Korea. This study was intended to describe the prevalence and related risk factors of delirium in intensive care unit (ICU). Methods: The Confusion Assessment Method for the ICU (CAM-ICU) data which were evaluated by nurses in ICUs was obtained through retrospective chart review. Data were analyzed using descriptive statistics, Chi-square test, t-test, Mann-Whitney U test, and stepwise logistic regression. Results: Delirium was evaluated in 125 patients. The incidence rate of delirium was 27.2% with a high prevalence of hypoactive delirium compared to hyperactive delirium (61.8 vs. 38.2%). Those with delirium were older, had hypertension, stayed longer in hospital, receiving ventilator support, had more number of catheters, had low serum protein and albumin level. Delirium incidence also varied according to diagnosis. Age, diagnosis of gastrointestinal disease, and application of ventilator were the significant risk factors for the incidence of delirium. Conclusion: Routine delirium screening is important for early detection of delirium. Identification of high-risk group and running delirium prevention programs could improve early recognition of delirium in ICU.

• 정보보호학회논문지
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• 제28권3호
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• pp.635-642
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• 2018

4차 산업혁명 시대에 우리는 소프트웨어 홍수 속에 살고 있다. 그러나, 소프트웨어의 증가는 필연적으로 소프트웨어 취약점 증가로 이어지고 있어 소프트웨어 취약점을 탐지 및 제거하는 작업이 중요하게 되었다. 현재까지 소프트웨어 취약 여부를 예측하는 연구가 진행되었지만, 탐지 시간이 오래 걸리거나, 예측 정확도가 높지 않았다. 따라서 본 논문에서는 기계학습 알고리즘을 이용하여 소프트웨어의 취약 여부를 효율적으로 예측하는 방법을 설명하며, 다양한 기계학습 알고리즘을 이용한 실험 결과를 비교한다. 실험 결과 k-Nearest Neighbors 예측 모델이 가장 높은 예측률을 보였다.

• 한국수산과학회지
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• 제49권2호
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• pp.224-233
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• 2016

The objective of this study was to develop an artificial neural network (ANN) model for the acoustic identification of commercially important fish species in Korea. A broadband echo acquisition and processing system operating over the frequency range of 85-225 kHz was used to collect and process species-specific, time-frequency feature images from six fish species: black rockfish Sebastes schlegeli, black scraper Thamnaconus modesutus [K], chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, konoshiro gizzard shad Konosirus punctatus and large yellow croaker Larimichthys crocea. An ANN classifier was developed to identify fish species acoustically on the basis of only 100 dimension time-frequency features extracted by the principal components analysis (PCA). The overall mean identification rate for the six fish species was 88.5%, with individual identification rates of 76.6% for black rockfish, 82.8% for black scraper, 93.8% for chub mackerel, 90.6% for goldeye rockfish, 96.9% for konoshiro gizzard shad and 90.6% for large yellow croaker, respectively. These results demonstrate that individual live fish in well-controlled environments can be identified accurately by the proposed ANN model.

• Journal of Trauma and Injury
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• 제27권4호
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• pp.115-125
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• 2014

Purpose: Stable vital signs (SVSs) are thought to be the most important criteria for successful non-operative management (NOM) of blunt spleen injury (BSI). However, a consistent definition of SVSs has been lacking. We wanted to evaluate the diversity of the definitions of SVSs by using a nationwide survey. Methods: A questionnaire regarding the definition of SVSs was sent to the trauma surgeons working at the Department of Trauma Surgery and Emergency Medicine at a level-I trauma center between October 2011 and November 2011. Data were compared using analyses of the variance, t-tests, ${\chi}^2$ tests and logistic regressions. Results: Among 201 surgeons, 198 responded (98.2%). Of these 198 responses, 45 were incomplete, so only 153 (76.1%) were analyzed. In defining the SVSs, significant diversity existed on the subjects of type of blood pressure (BP), cut-off value for hypotension, technique for measuring BP, duration of hypotension, whether or not to use the heart rate (HR) as a determinant, cut-off value of hypotension when the patient had a comorbidity or when the patient was a child. Of the 153 surgeons whose responses were analyzed, 91.5% replied that they were confused when defining SVSs. Conclusion: Confusion exists regarding how to define SVSs. Most surveyed surgeons felt that a need existed to clarify both the definition of SVSs and the use of SVSs to determine hemodynamic stability for NOM.