• Journal of Radiation Protection and Research
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• 제48권1호
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• pp.9-14
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• 2023

Background: The detectors of both computed radiography (CR) and direct digital radiography (DR) have a wide dynamic range that could tolerate high values of exposure factors without an adverse effect on image quality. Therefore, this study aims to assess patient radiation dose and proposes institutional diagnostic reference levels (DRLs) for two teaching hospitals in Ghana. Materials and Methods: CR and DR systems were utilized in this study from two teaching hospitals. The CR system was manufactured by Philips Medical Systems DMC GmbH, while the DR system was manufactured by General Electric. The entrance skin doses (ESDs) were calculated using the standard equation and the tube output measurements. Free-in-air kerma (µGy) was measured using a calibrated radiation dosimeter. The proposed institutional DRLs were estimated using 75^th percentiles values of the estimated ESDs for nine radiographic projections. Results and Discussion: The calculated DRLs were 0.4, 1.6, 3.4, 0.5, 0.4, 1.1, 1.0, 1.2, and 1.7 mGy for chest posteroanterior (PA), lumbar spine anteroposterior (AP), lumbar spine lateral (LAT), cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively in CR system. In the DR system, the values were 0.3, 1.6, 3.1, 0.4, 0.3, 0.7, 0.6, 0.9, and 1.3 for chest PA, lumbar spine AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively. Conclusion: Institutional DRLs in nine radiographic projections have been proposed for two teaching hospitals in Ghana for the first time. The proposed DRLs will serve as baseline data for establishing local DRLs in the hospitals and will be a valuable tool in optimizing patient doses.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권6호
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• pp.1706-1727
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• 2023

Under Water Sensor Networks (UWSN) has gained attraction among various communities for its potential applications like acoustic monitoring, 3D mapping, tsunami detection, oil spill monitoring, and target tracking. Unlike terrestrial sensor networks, it performs an acoustic mode of communication to carry out collaborative tasks. Typically, surface sink nodes are deployed for aggregating acoustic phenomena collected from the underwater sensors through the multi-hop path. In this context, UWSN is constrained by factors such as lower bandwidth, high propagation delay, and limited battery power. Also, the vulnerabilities to compromise the aquatic environment are in growing numbers. The paper proposes an Energy-Efficient standalone Intrusion Detection System (EEIDS) to entail the acoustic environment against malicious attacks and improve the network lifetime. In EEIDS, attributes such as node ID, residual energy, and depth value are verified for forwarding the data packets in a secured path and stabilizing the nodes' energy levels. Initially, for each node, three agents are modeled to perform the assigned responsibilities. For instance, ID agent verifies the node's authentication of the node, EN agent checks for the residual energy of the node, and D agent substantiates the depth value of each node. Next, the classification of normal and malevolent nodes is performed by determining the score for each node. Furthermore, the proposed system utilizes the sheep-flock heredity algorithm to validate the input attributes using the optimized probability values stored in the training dataset. This assists in finding out the best-fit motes in the UWSN. Significantly, the proposed system detects and isolates the malicious nodes with tampered credentials and nodes with lower residual energy in minimal time. The parameters such as the time taken for malicious node detection, network lifetime, energy consumption, and delivery ratio are investigated using simulation tools. Comparison results show that the proposed EEIDS outperforms the existing acoustic security systems.

• Steel and Composite Structures
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• 제52권2호
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• pp.145-163
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• 2024

This paper presents six novel hybrid machine learning (ML) models that combine support vector machines (SVM), Decision Tree (DT), Random Forest (RF), Gradient Boosting (GB), extreme gradient boosting (XGB), and categorical gradient boosting (CGB) with the Harris Hawks Optimization (HHO) algorithm. These models, namely HHO-SVM, HHO-DT, HHO-RF, HHO-GB, HHO-XGB, and HHO-CGB, are designed to predict the ultimate strength of both rectangular and circular reinforced concrete (RC) columns. The prediction models are established using a comprehensive database consisting of 325 experimental data for rectangular columns and 172 experimental data for circular columns. The ML model hyperparameters are optimized through a combination of cross-validation technique and the HHO. The performance of the hybrid ML models is evaluated and compared using various metrics, ultimately identifying the HHO-CGB model as the top-performing model for predicting the ultimate shear strength of both rectangular and circular RC columns. The mean R-value and mean a20-index are relatively high, reaching 0.991 and 0.959, respectively, while the mean absolute error and root mean square error are low (10.302 kN and 27.954 kN, respectively). Another comparison is conducted with four existing formulas to further validate the efficiency of the proposed HHO-CGB model. The Shapely Additive Explanations method is applied to analyze the contribution of each variable to the output within the HHO-CGB model, providing insights into the local and global influence of variables. The analysis reveals that the depth of the column, length of the column, and axial loading exert the most significant influence on the ultimate shear strength of RC columns. A user-friendly graphical interface tool is then developed based on the HHO-CGB to facilitate practical and cost-effective usage.

• 한국조리학회지
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• 제22권4호
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• pp.81-94
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• 2016

본 연구의 목적은 외식관련 전공자의 노동시장 이행에 영향을 미치는 요인에 대한 상대적 중요도를 측정하고자 한다. 이러한 목적을 달성하기 위해 외식관련 전공자의 노동시장 이행에 영향을 미치는 요인들로서 개인배경, 학력, 노동시장 이행 준비노력 요인 등을 계층 2로 설정하였으며, 계층에 있는 요소들에 대한 상대 평가를 통해 각 요소들이 가지는 중요도를 산출해 내는 기법인 계층분석기법을 사용하였다. 분석결과를 살펴보면 다음과 같다. 첫째, 계층 2의 경우 노동시장 이행 준비노력의 상대적 중요도가 가장 높게 나타났다. 반면에, 4년제 대학의 외식관련 전공자의 경우, 학력 요인의 상대적 중요도가 가장 높게 나타났다. 둘째, 계층 3 중 개인배경요인의 경우 성별의 상대적 가중치가 가장 높게 나타났다. 학력 요인의 경우, 대학유형의 상대적 가중치가 가장 높게 나타났다. 노동시장 이행 준비노력 요인의 경우, 재학 중 국외 근로경험과 구직경로의 상대적 가중치가 높게 나타났으며, 직업훈련 경험의 상대적 가중치는 가장 낮게 나타났다. 셋째, 복합 가중치를 분석한 결과를 살펴보면 대학유형의 복합가중치가 가장 높게 나타났다. 향후 연구에서는 외식관련 산업체의 업종과 업태를 보다 세분화하여 영향 요인을 분석하고, 이를 토대로 전공자의 진로분야별 맞춤형 진로지도가 이루어져야 할 것이다.

• 대한공업교육학회지
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• 제35권2호
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• pp.43-69
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• 2010

이 연구는 한국교육학술정보원(RISS), 한국학술정보(KISS), 누리미디어(DBPIA)에서 검색된 98편의 공업계열 전기 전자 통신교육과 관련된 논문을 가지고 국내 전기 전자 통신교육 관련 연구가 시작된 1973년부터 2010년 현재까지의 학술지 논문과 학위논문을 중심으로 분석, 종합하고 공업 교육의 전기 전자 통신교육 분야의 연구 동향을 분석하여 이를 바탕으로 앞으로의 전기 전자 통신교육과 관련된 연구의 방향과 시사점을 제공하는 것을 목적으로 수행되었다. 이 연구를 위해 3인의 연구자가 분석연구의 방법으로 연구를 진행하였다. 연구의 결과로부터 얻은 결론은 다음과 같다. 첫째, 초기 전기 전자 통신교육 관련 연구는 1980년대 이전에도 전체 98편 가운데 2편(2.04%)의 연구가 이루어졌고, 그로부터 1995년도 이전까지는 전기 전자 통신교육 관련 연구가 5편(5.10%)으로 미진했으나 1996년부터 현재까지 논문의 수가 91편으로 전체 연구의 92.86%에 해당하는 연구가 이루어져 계속적으로 증가하는 추세이다. 둘째, 교과영역 연구는 수업자료의 설계 및 개발을 주제로 한 영역이 가장 많이 연구되었고, 가장 저조한 연구 경향을 보이고 있는 영역은 교육평가 영역이었다. 교과내용 영역 연구는 전자공학 분야가 가장 많이 연구되었고, 그 다음으로 전기공학, 통신공학의 순이었다. 최종 분석 대상인 98편의 연구들 중 50편의 연구는 교과교육 영역만을 주제로 한 연구였다. 연구방법별 연구는 조사연구, 개발연구, 문헌고찰, 내용분석, 실험연구, 사례연구, 기타의 순으로 분석되었다. 발표지 유형별 연구는 학위논문, 학술지논문의 순이었으며, 연구대상별 연구는 학생이 연구대상으로 가장 많이 선정되었고, 교사, 문헌, 산업체 근로자, 전문가 순으로 학생과 문헌, 교사에 너무 편중되는 경향이 있었다. 또한 연구기관별 연구는 대학교에서 가장 많이 연구되었고, 고등학교, 연구소의 순이었다. 마지막으로 연구자 근무지역별 연구는 근무지가 충청권인 연구자의 논문이 가장 많았고, 서울 경기권, 영남권, 호남권, 강원 제주권의 순이었다.

• 한국수학교육학회지시리즈A:수학교육
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• 제31권2호
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• pp.109-119
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• 1992

The primary purpose of the present study is to provide the sources to improve the mathematical problem solving performance by analyzing the effects of the belief systems and the misconceptions of the middle school students in solving the problems. To attain the purpose of this study, the reserch is designed to find out the belief systems of the middle school students in solving the mathematical problems, to analyze the effects of the belief systems and the attitude on the process of the problem solving, and to identify the misconceptions which are observed in the problem solving. The sample of 295 students (boys 145, girls 150) was drawn out of 9th grade students from three middle schools selected in the Kangdong district of Seoul. Three kinds of tests were administered in the present study: the tests to investigate (1) the belief systems, (2) the mathematical problem solving performance, and (3) the attitude in solving mathematical problems. The frequencies of each of the test items on belief systems and attitude, and the scores on the problem solving performance test were collected for statistical analyses. The protocals written by all subjects on the paper sheets to investigate the misconceptions were analyzed. The statistical analysis has been tabulated on the scale of 100. On the analysis of written protocals, misconception patterns has been identified. The conclusions drawn from the results obtained in the present study are as follows; First, the belief systems in solving problems is splited almost equally, 52.95% students with the belief vs 47.05% students with lack of the belief in their efforts to tackle the problems. Almost half of them lose their belief in solving the problems as soon as they given. Therefore, it is suggested that they should be motivated with the mathematical problems derived from the daily life which drew their interests, and the individual difference should be taken into account in teaching mathematical problem solving. Second. the students who readily approach the problems are full of confidence. About 56% students of all subjects told that they enjoyed them and studied hard, while about 26% students answered that they studied bard because of the importance of the mathematics. In total, 81.5% students built their confidence by studying hard. Meanwhile, the students who are poor in mathematics are lack of belief. Among are the students accounting for 59.4% who didn't remember how to solve the problems and 21.4% lost their interest in mathematics because of lack of belief. Consequently, the internal factor accounts for 80.8%. Thus, this suggests both of the cognitive and the affective objectives should be emphasized to help them build the belief on mathematical problem solving. Third, the effects of the belief systems in problem solving ability show that the students with high belief demonstrate higher ability despite the lack of the memory of the problem solving than the students who depend upon their memory. This suggests that we develop the mathematical problems which require the diverse problem solving strategies rather than depend upon the simple memory. Fourth, the analysis of the misconceptions shows that the students tend to depend upon the formula or technical computation rather than to approach the problems with efforts to fully understand them This tendency was generally observed in the processes of the problem solving. In conclusion, the students should be taught to clearly understand the mathematical concepts and the problems requiring the diverse strategies should be developed to improve the mathematical abilities.

• 대한공업교육학회지
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• 제31권2호
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• pp.64-82
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• 2006

이 연구에서는 학습자 개인의 다양한 지적 능력을 파악할 수 있는 다중지능이 성별에 따라 기술적 문제해결력에 어떠한 영향을 미치고 있는가를 조사하여, 성별에 따른 기술적 문제해결력의 차이를 줄이기 위한 방안을 제시하고자 한다. 연구의 대상은 광역시 이상에 소재한 중학교 3학년 833(남학생 423, 여학생 410)명이었고, 문용린(2001)과 1998년 CRESST에서 개발한 도구를 사용하였다. 연구의 결과 첫째, 신체운동지능, 논리수학지능, 자연친화지능, 음악지능, 대인관계지능, 자기성찰지능은 남학생과 여학생간에 통계적으로 유의한 차이가 있는 것으로 밝혀졌다. 둘째, 기술적 문제해결력의 자기조절성향과 문제해결전략에서 남학생과 여학생간에 통계적으로 유의한 차이가 있는 것으로 밝혀졌다. 셋째, 자기조절성향에 영향을 미치는 다중지능으로 남학생은 논리수학지능, 언어지능, 자기성찰지능, 자연친화지능, 여학생은 논리수학지능, 자기성찰지능, 자연친화지능, 언어지능으로 밝혀졌다. 넷째, 문제해결력에 영향을 미치는 다중지능으로 남학생은 논리수학지능, 음악지능, 신체운동지능, 여학생은 언어지능과 음악지능으로 밝혀졌다. 다섯째, 지식 개념도 작성에 영향을 미치는 다중지능으로는 남학생과 여학생 모두 논리수학지능으로 밝혀졌다. 연구의 결과 나타난 성별에 따른 차이를 줄이기 위해, 초 중등학교 교육과정 개발에 다중지능과 직 간접적으로 관련된 분야를 집중적으로 개발할 수 있도록 고려한다면 다중지능의 차이에 의해서 발생되는 학업성취도 차이를 어느 정도 극복할 수 있을 것으로 판단된다.

• 지능정보연구
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• 제21권1호
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• pp.15-28
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• 2015

최근 개인 단말기의 보급과 객체간의 네트워크 연결이 확산됨에 따라 방대한 양의 상황 정보들이 수집되고 있지만 역설적으로 사용자들과 서비스 제공자들은 정보의 홍수 속에서 종종 잘못된 의사결정을 내리고 있다. 이러한 정보 과부하 문제를 해결하기 위해 추천 시스템은 좋은 대안이 될 수 있지만 전통적인 추천 시스템은 다양한 형태의 상황 정보 사용에 한계를 보이고 있다. 또한 획득 가능한 상황 정보가 다양해지고 방대해짐에 따라 이를 활용한 추천 시스템은 복잡성의 문제를 해결해야 하며 지속적으로 변화되는 사용자 선호 및 상황에 부합할 수 있도록 실시간 서비스가 가능하도록 설계되어야 한다. 따라서 본 연구에서는 상황 영역의 개념을 기반으로 한 상황 인식 추천 서비스 방법론을 제안하여 추천 시스템에서 상황정보를 활용하는 한편 복잡성 및 실시간 서비스 제공의 문제를 해결하려 한다. 먼저 적절한 해석과 구조로 상황 데이터를 사용자 프로필에 반영할 수 있도록 상황 영역 개념에 기반한 프로파일링을 제안함에 따라 기존의 상황 인식 추천 시스템이 가지고 있던 복잡성의 한계를 해결하고자 한다. 다음으로 목표 사용자의 상황 영역에 기반한 이웃 집단 탐색으로 추천 시스템의 희박성과 신규 사용자 문제를 해결하는 한편 현재의 상황 정보에 대한 해석으로 도출되는 상황 지지 점수를 기반으로 한 추천 목록을 생성하여 실시간 서비스가 가능한 방법론을 제안한다. 결론적으로 본 연구에서 제안하는 방법론은 추천 시스템의 적용 영역을 확장하는 연구가 될 것으로 기대되며 새로운 기술 출현을 고려한 유연한 모델을 제안함에 따라 마케팅 담당자나 서비스 제공자들이 쉽게 본 연구에서 제안하는 방법론을 적용할 수 있으리라 판단된다.

• Asia pacific journal of information systems
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• 제23권4호
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• pp.129-149
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• 2013

According to the development of new Information Technologies, firms consistently invest a significant amount of money in IT activities, such as establishing internal and external information systems. However, several anti-Information activities-such as hacking, leakage of information and system destruction-are also rapidly increasing, thus many firms are exposed to direct and indirect threats. Therefore, firms try to establish information security systems and manage these systems more effectively via an enterprise perspective. However, stakeholders or some managers have negative opinions about information security systems. Therefore, in this research, we study the relationship between multibusiness firms' performance and information security systems. Information security indicates physical and logical correspondence of information system department against threats and disaster. Studies on information security systems suggested frameworks such as IT Governance Cube and COBIT Framework to identify information security systems. Thus, this study define that information security systems is a controlled system on enterprise IT process and resource on IT Governance perspective rather than independent domain of IT. Thus, Information Security Systems should be understood as a subordinate concept of IT and business processes. In addition, this study incorporates information capability to information security system literature to show the positive relationship between Information Security Systems and Corporate Performance. The concept of information capability suggested that an interaction of human, information, technical and an effect on corporate performance using three types of capability (IT Practice, Information Management Practice, Information Behaviors and Values). Information capability is about firms' capability to manage IT infrastructure and information as well as individual employees who use IT infrastructure and information. Thus, this study uses information capability as a mediating variable for the relationship between information security systems and firms' performance. To investigate the relationship between Information Security Systems and multibusiness firms' performance, this study extends the IT relatedness concept into Information Security Systems. IT relatedness provides understanding of how corporations cope with conflicts between headquarters and business units to create a synergy effect and achieve high performance using IT resources. Based on the previous literature, this study develops the IT Security Relatedness model. IT Security Relatedness is our main independent variable, while Information Capability and Information Security Performance are mediating variables. To control for the common method bias, we collect each multibusiness firm's financial performance and use it as our dependent variable. We find that Information Security Systems influence Information Capability and Information Security Performance positively, and these two variables consequently influence Corporate Performance positively. In addition, this result indirectly shows that corporations under a multibusiness environment can obtain synergy effects using the integrated Information Security Systems. This positive impact of Information Security Systems on multibusiness firms' performance has an important implication to various stakeholders. Therefore, multibusiness firms need to establish Information Security Systems to achieve better financial performance.

• 대한물리치료과학회지
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• 제9권3호
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• pp.31-49
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• 2002

The purpose of this study was to investigate discomforts and sexual life and to identify the relation between the discomforts and sexual life with low back pain. The data were collected from March 2 through July 31, 2001. Four hundred forty-two questionnaires were returned (response rate=88.0%). Analysis of the data was done with SPSS PC+ and use descriptive statistics, $x^2$-test, t-test, ANOVA. regression. The statistics shows that over than 80% of the adults experienced lumbago at least one time in their life, and Back pain is known as one of the most common complaints made by the patients of all ages in the general hospital or local medical clinics throughout. However, in certain case it leads to a chronic condition which can cause a great deal of problems in management and in financial burden to individuals and society. The result of this study was summarized as follows: 1) It appeared that regarding the distribution of gender, male was the higher(63.6%) then that of female, the portion of forties was 28.5%. Sitting for long time was 23.1% in men and 21.7% in women. Unknown reason including sexual behaviour was 12.9% in men and 15.5% in women. Patients treated medicine and physical therapy were 36.4%. In level of educational background, the rate of high school was 31.0%, technical college was 28.5%. The highest proportion by occupation was 18.3% of office workers, occupation posture was 41.9% of sitting. 2) Men(26.0%) and most of women(34.8%) were not satisfied in the explanation satisfaction rate of sex life concerned disease. 23.8% in men and 23.6% in women considered flexibility of waist good. Man(33.3%) and most of woman(35.0%) considered that Health education is necessary. 32.7% in men and 27.3% in women did't mind educator is whoever. Preventing of lower back pain(LBP) and proper Health education of sex life are demanded in daily life. 3) 58.0% of man and 64.0% of woman mostly had a posture which is man over woman. 28.5% in men and 27.8% in women considered that proper information finding of LBP and sex life was very few and few. 37.7% in men and 42.7% in women have acquired information about sex life flung their friends. 4) The number of sex life was decreased from 2.96 0.98 to 2.61 1.63 and also the time of sex life was decreased from 3.65 1.89 to 226 1.64. The satisfaction rate of sex life changed from 3.60 0.86 to 2.77 1.10. In the number of sex life, The non correct group was 2.62 1.91 and the correct group was higher in 2.68 1.65. In the time of sex life, The non correct group was 2.02 1.47 and the correct group was higher in 229 1.65. The satisfaction rate of sex life was 2.76 0.86 in non correct group and 2.88 1.10 in correct group. So there was a difference. 5) In the satisfaction rate of sex life, Men who have a lower back pain were higher than women and no attack group was higher than attack group. As they had many sex life, the satisfaction rate was higher significantly in statistics. As the time of sex life was short, the satisfaction rate was lower significantly in statistics. As the age was low, the demand rate of Health education was high and as means of patient who had a lower back pain was high, the demand rate of Health education was high. As the patient who had a lower back pain had a long married life, the demand rate of Health education was high and as education level was high, the demand rate of Health education was high. It is necessary to provide patients with conservative treatment, educational teaching, and training to prevent further injuries in the future. In general, it is important to educate the public how to prevent back injuries and how to treat themselves in an onset period to prevent further injuries sliding into a chronic state. Sexuality is an integral part of normal and healthy relationships, but patients are unable to enjoy sex because they are riot able to get into a comfortable position due to back pain. Many conditions of the spine can make certain positions uncomfortable. Health educator should make the education program of the discomforts and the sexual pattern for low back pain in workplace and/or hospital. Further study Is needed on how to integrate the educational program on sexuality into the total rehabilitation program.