• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.313-322
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• 2020

The recognition of the risk hazards is a vital step to effectively prevent accidents on a construction site. The advanced development in computer vision systems and the availability of the large visual database related to construction site made it possible to take quick action in the event of human error and disaster situations that may occur during management supervision. Therefore, it is necessary to analyze the risk factors that need to be managed at the construction site and review appropriate and effective technical methods for each risk factor. This research focuses on analyzing Occupational Safety and Health Agency (OSHA) related to risk zone identification rules that can be adopted by the image recognition technology and classify their risk factors depending on the effective technical method. Therefore, this research developed a pattern-oriented classification of OSHA rules that can employ a large scale of safety hazard recognition. This research uses joint reasoning of risk zone Identification and numeric input by utilizing a stereo camera integrated with an image detection algorithm such as (YOLOv3) and Pyramid Stereo Matching Network (PSMNet). The research result identifies risk zones and raises alarm if a target object enters this zone. It also determines numerical information of a target, which recognizes the length, spacing, and angle of the target. Applying image detection joint logic algorithms might leverage the speed and accuracy of hazard detection due to merging more than one factor to prevent accidents in the job site.

• 한국학교보건학회지
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• 제36권3호
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• pp.113-125
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• 2023

Purpose: The purpose of this study is to develop a model for predicting mental health risk among adolescents based on health behavior information by employing a hybrid machine learning method. Methods: The study analyzed data of 51,850 domestic middle and high school students from 2022 Youth Health Behavior Survey conducted by the Korea Disease Control and Prevention Agency. Firstly, mental health risk levels (stress perception, suicidal thoughts, suicide attempts, suicide plans, experiences of sadness and despair, loneliness, and generalized anxiety disorder) were classified using the k-mean unsupervised learning technique. Secondly, demographic factors (family economic status, gender, age), academic performance, physical health (body mass index, moderate-intensity exercise, subjective health perception, oral health perception), daily life habits (sleep time, wake-up time, smartphone use time, difficulty recovering from fatigue), eating habits (consumption of high-caffeine drinks, sweet drinks, late-night snacks), violence victimization, and deviance (drinking, smoking experience) data were input to develop a random forest model predicting mental health risk, using logistic and XGBoosting. The model and its prediction performance were compared. Results: First, the subjects were classified into two mental health groups using k-mean unsupervised learning, with the high mental health risk group constituting 26.45% of the total sample (13,712 adolescents). This mental health risk group included most of the adolescents who had made suicide plans (95.1%) or attempted suicide (96.7%). Second, the predictive performance of the random forest model for classifying mental health risk groups significantly outperformed that of the reference model (AUC=.94). Predictors of high importance were 'difficulty recovering from daytime fatigue' and 'subjective health perception'. Conclusion: Based on an understanding of adolescent health behavior information, it is possible to predict the mental health risk levels of adolescents and make interventions in advance.

• 인터넷정보학회논문지
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• 제24권6호
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• pp.23-29
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• 2023

가상현실 분야에서는 사용자 경험의 몰입도를 극대화하기 위해 햅틱 피드백을 활용하고 발전시키려는 지속적인 노력이 있었다. 그러나 대부분의 햅틱 피드백은 진동 모터 등 경제성을 고려한 액추에이터를 사용하는 문제로 인해 제한적인 촉각 경험만을 사용자에게 제공할 수 있었다. 복싱과 같은 스포츠 시뮬레이션이나 게임에서의 타격 경험의 경우, 실제 물체를 타격하는 감각과 진동 액추에이터로 렌더링되는 감각 사이의 괴리 때문에 한계가 분명하다. 본 연구에서는 이를 주목하여, 사용자가 손으로 가상의 물체를 타격할 때 가상 임팩트를 생성할 수 있는 햅틱 임팩트 시스템을 제안했다. 햅틱 인터페이스는 퀵 리턴 메커니즘을 사용하여 엔드이펙터가 사용자의 주먹에 햅틱 임팩트 피드백을 직접 전달하고 진동 촉감을 통해서 사용자의 손바닥에 가상 임팩트 감각을 전달할 수 있도록 하였다. 제안된 시스템은 인간 대상 실험을 통해 평가하였으며 실험 결과는 햅틱 임팩트 가상 임팩트의 인지 강도와 사실감에 유의한 영향을 미친다는 것을 나타낸다.

• 대한의용생체공학회:의공학회지
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• 제44권6호
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• pp.392-403
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• 2023

This study presents a new hybrid fNIRS-EEG system to meet the demand for a lightweight and low-cost sleep pattern monitoring device. For multiple-channel configuration, a six-channel electroencephalogram (EEG) and a functional near-infrared spectroscopy (fNIRS) system with eight photodiodes (PD) and four dual-wavelength LEDs are designed. To enhance the convenience of signal measurement, the device is miniaturized into a patch-like form, enabling simultaneous measurement on the forehead. Due to its fully integrated functionality, the developed system is advantageous for performing sleep stage classification with high-temporal and spatial resolution data. This can be realized by utilizing a two-dimensional (2D) brain activation map based on the concentration changes in oxyhemoglobin and deoxyhemoglobin during sleep stage transitions. For the system verification, the phantom model with known optical properties was tested at first, and then the sleep experiment for a human subject was conducted. The experimental results show that the developed system qualifies as a portable hybrid fNIRS-EEG sleep pattern monitoring device.

• 한국산업정보학회논문지
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• 제29권1호
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• pp.107-116
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• 2024

Copper Filter Dryer(CFD)는 냉동 및 냉방 시스템에서 냉매의 순환 시 불순물을 제거하여 깨끗한 냉매를 유지하는 역할을 하며, CFD의 결함은 냉동 및 냉방 시스템의 누수, 수명 저하 등 제품의 결함으로 이어질 수 있어 품질보증이 필수적이다. 기존에는 품질 검사 단계에서 작업자가 검사하고 결함을 판단하는 방법이 주로 사용되었으나, 이러한 방법은 주관적으로 판단하기 때문에 정확하지 못하다. 본 논문에서는 CFD 축관 및 용접 공정 과정에서 발생하는 결함을 검출하고 기존의 품질 검사를 대체하기 위해 YOLOv7 객체 감지 알고리즘을 사용하여 결함을 검출했고, F1-Score 0.954, 0.895의 검출 성능을 확인하였다. 또한, 결함 이미지의 Timestamp에 해당하는 센서 데이터 분석을 통해 용접 과정 중 발생하는 결함의 원인을 분석하였다. 본 논문은 CFD 공정 중 발생하는 결함을 검출하고 원인을 분석함으로써 제조 품질보증과 개선 방안을 제시한다.

• Safety and Health at Work
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• 제14권4호
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• pp.368-374
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• 2023

Background: Recognizing that access to safe and healthy working conditions is a human right, the World Health Organization (WHO) calls for specific occupational safety and health (OSH) programs for health workers (HWs). The WHO health systems' building blocks, and the International Labour Organization (ILO), highlight the importance of information as part of effective systems. This study examined how OSH stakeholders access, use, and value an occupational health information system (OHIS). Methods: A cross-sectional survey of OSH stakeholders was conducted as part of a larger quasi experimental study in four teaching hospitals. The study hospitals and participants were purposefully selected and data collected using a modified questionnaire with both closed and open-ended questions. Quantitative analysis was conducted and themes identified for qualitative analysis. Ethics approval was provided by the University of Pretoria and University of British Columbia. Results: There were 71 participants comprised of hospital managers, health and safety representatives, trade unions representatives and OSH professionals. At least 42% reported poor accessibility and poor timeliness of OHIS for decision-making. Only 50% had access to computers and 27% reported poor computer skills. When existing, OHIS was poorly organized and needed upgrades, with 85% reporting the need for significant reforms. Only 45% reported use of OHIS for decision-making in their OSH role. Conclusion: Given the gap in access and utilization of information needed to protect worker's rights to a safe and healthy workplace, more attention is warranted to OHIS development and use as well as education and training in South Africa and beyond.

• 대한불안의학회지
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• 제20권1호
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• pp.8-16
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• 2024

Objective : The purpose of this study is to compare the signal obtained from the frontal 2-electrodes EEG with that obtained from the temporal, central, and parietal 2 electrodes. Methods : EEGs were recorded in a total of 67 patients with major depressive disorder (MDD), 104 patients with schizophrenia (SCZ), and 29 patients with Alzheimer's disease (AD). For each disease group, there were healthy controls (HC) that were paired accordingly (HC1=69, HC2=104, HC3=27). The following measurements were compared across electrodes: band power, alpha peak frequency (APF), APF power, alpha asymmetry (AA), and Kolmogorov complexity (KC). Results : Statistically significant differences were found in band power measured from frontal electrodes compared to electrodes placed in other locations. Specifically, the power of theta waves was measured higher in the temporal electorodes, alpha 1 and alpha 2 waves in the parietal, beta 1 and beta 2 in the central, and gamma waves in the temporal electrodes. Both SCZ and AD patients showed increased theta power in all electrodes. In SCZ patients, APF decreased in the central and temporal electrodes, but the APF power analysis showed no difference between the patients and controls. Additionally, AD patients exhibited increased AA in the central EEG, while SCZ patients showed decreased KC in the parietal and temporal electrodes. Conclusion : Depending on the electrode location, sensitive EEG frequencies differed. Compared with signals from other electrodes, frontal EEG in MDD patients revealed generally constant signal values, though the temporo-parieto-central electrodes appeared to be more reliable in SCZ and AD patients.

• Korean Journal of Radiology
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• 제22권11호
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• pp.1797-1808
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• 2021

Objective: To determine whether volumetric CT texture analysis (CTTA) using fully automatic tumor segmentation can help predict recurrence-free survival (RFS) in patients with intrahepatic mass-forming cholangiocarcinomas (IMCCs) after surgical resection. Materials and Methods: This retrospective study analyzed the preoperative CT scans of 89 patients with IMCCs (64 male; 25 female; mean age, 62.1 years; range, 38-78 years) who underwent surgical resection between January 2005 and December 2016. Volumetric CTTA of IMCCs was performed in late arterial phase images using both fully automatic and semi-automatic liver tumor segmentation techniques. The time spent on segmentation and texture analysis was compared, and the first-order and second-order texture parameters and shape features were extracted. The reliability of CTTA parameters between the techniques was evaluated using intraclass correlation coefficients (ICCs). Intra- and interobserver reproducibility of volumetric CTTAs were also obtained using ICCs. Cox proportional hazard regression were used to predict RFS using CTTA parameters and clinicopathological parameters. Results: The time spent on fully automatic tumor segmentation and CTTA was significantly shorter than that for semi-automatic segmentation: mean ± standard deviation of 1 minutes 37 seconds ± 50 seconds vs. 10 minutes 48 seconds ± 13 minutes 44 seconds (p < 0.001). ICCs of the texture features between the two techniques ranged from 0.215 to 0.980. ICCs for the intraobserver and interobserver reproducibility using fully automatic segmentation were 0.601-0.997 and 0.177-0.984, respectively. Multivariable analysis identified lower first-order mean (hazard ratio [HR], 0.982; p = 0.010), larger pathologic tumor size (HR, 1.171; p < 0.001), and positive lymph node involvement (HR, 2.193; p = 0.014) as significant parameters for shorter RFS using fully automatic segmentation. Conclusion: Volumetric CTTA parameters obtained using fully automatic segmentation could be utilized as prognostic markers in patients with IMCC, with comparable reproducibility in significantly less time compared with semi-automatic segmentation.

• 한국의상디자인학회지
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• 제4권1호
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• pp.111-130
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• 2002

This study performed a structural questionnaire survey and non-structural interview of the ladies apparel manufacturers in Daegu on the qualification for the employees, skills required for job performance, job training, automatic manufacturing systems, and the use of computer. The results are as follows. 1. Almost all of the apparel manufacturing systems were Pair System, except one Line System in one company. In terms of outsourcing, most of the manufacturers answered “yes,” and in 1998 the outsourcing process was sewing, but in the year 2002, outsourcing has been increased :12 manufacturers(57.1%) outsourcing most of the processes except patterning, 3(14.3%) outsourcing the finish of sewing. 2. The workforce of 1998 and that of 2002 shows a significant difference(P＜. 01) between office work and management. The number of office workers has decreased from 15 down to 5.3 people. On the other hand, that of the management has slightly increased from 5.3 to 9.2 people. The number of the manual workers has decreased from 32.2 to 28.7 people. And the number of tailoring and patterning workers has slightly decreased, but the number has increased in sewing from 3.7 to 7.0 people. 3. The wage of an employee shows a significant difference between a sewing assistant(P＜. 01) and a production manager(P＜. 05), and the wage of a sewing assistant, in particular, has slightly raised from ￦905,000 to ￦1,054,000. 4. The qualifications required of employees are “cooperative human relations”(30.8％), “diligence,” and “ability for job analysis”(26.9％), and “positive thinking” (15.4％) in 1998, and “ability for job analysis”(38.5％), “cooperative human relations”(34.6％), and “positive thinking” (15.4％) in 2002. The areas for job openings are significantly different(P＜. 01) depending on the year. Job openings in the design section has increased from 1(3.8％) to 16 manufacturers (61.5％), and decreased in tailoring section from 22(84.6％) to 2 manufacturers(7.7％). Job openings in the sewing section have increased form 2(7.7％) to 6 manufacturers (23.1％). In terms of sex of the employees, there is a significant difference(P＜. 001). 19 companies(73.1％) wanted “male” in 1998, but 8 companies(30.8％) answered that they want “female” and 17 companies(65.4％) answered that “it does not matter.” About the educational background, there was a significant difference between the years. The number of the companies that want junior college graduates with an associate degree has increased(15 companies(57.7％). There was a significant difference(P＜. 05) in major of the employee. The number of the companies that want fashion majors has increased from 5(19.2％) to 20(76.9％). 5. In terms of job skills required, there was no significant difference. In 1998, “production skills” (46.2％) and “ability for job analysis” (26.9％) were required, and in 2002, “ability for job analysis” (42.3％) and “emotional skills” (26.9％). 6. In regard to training for job skills, “fashion professional training” has slightly decreased from 65.4％ in 1998 to 46.2％ in 2002, however, “training for job analysis” has slightly increased from 30.8％ in 1998 to 46.2％ in 2002, which indicates the fact that “fashion professional training” and “ability for job analysis” have been emphasized. 7. The number of the manufacturers purchased apparel CAD has increased from 1(3.8％) to 3(11.5％), and the number of the manufacturers that have no plan for purchase has increased from 16(61.5％) in 1998 to 15(57.7％), still taking up a big proportion. 8. About the use of computers in manufacturing, there is a significant difference(P＜. 05). The number of the manufacturers using computer has increased from 5(19.2％) to 15(57.7％) and that of the manufacturers which do not use computers has decreased from 17(57.7％) to 8(30.8％). 9. In the interviews with the owners of the manufacturers, they pointed that schools should give more weight on practical training courses, the invitation of experts in the specific field, complex production systems, training courses for sewing, field trip courses, and furthering specialty education, personality and vocational education.

• 경영정보학연구
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• 제21권4호
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• pp.143-156
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• 2019

혁신의 유형은 단순화, 정보화, 자동화, 지능화로 분류할 수 있고 지능화는 혁신의 최상위 단계이며 RPA는 지능화의 하나로 볼 수 있다. 인공지능을 가미한 소프트웨어 로봇인 RPA(Robotic Process Automation)는 단순 반복적인 대량의 트랜젝션 처리 작업을 하는 곳에 적합한 지능화 사례이다. 이미 국내의 많은 기업들에서도 현재 운영 중에 있는 RPA는 강한조직 문화의 필요성이 증대되면서 자발적인 리더십, 강한 팀워크와 실행력, 프로답게 일하는 문화가 강조되는 상황에서 자연스럽게 핵심적 업무에 집중하기 위해 필요한 것이 무엇인지를 찾고자 하는 필요성에 따라 자연스럽게 도입이 검토되고 있다. 로봇 프로세스 자동화 또는 RPA는 구조적인 작업을 빠르고 효율적으로 처리하는 것을 목표로 인간 업무를 교체하는 기술이다. RPA는 ERP 시스템이나 생산성 도구와 같은 소프트웨어를 사용하여 사람을 모방한 소프트웨어 로봇을 통해 구현된다. RPA 로봇은 컴퓨터에 설치된 소프트웨어로 작동 원리에 의해 로봇으로 불리다. RPA는 백엔드를 통해 다른 IT 시스템과 통신하는 기존 소프트웨어와 달리 프런트 엔드를 통해 IT 시스템 전체에 통합된다. 실제로 이것은 소프트웨어 로봇이 인간과 똑 같은 방식으로 IT 시스템을 사용하고 정확한 단계를 반복하며 시스템의 API(Application Programming Interface)와 통신하는 대신 컴퓨터 화면의 이벤트에 반응하는 것을 의미한다. 다른 소프트웨어와 의사소통하기 위해 인간을 모방하는 소프트웨어를 설계하는 것은 직관력이 떨어질 수 있지만 이러한 접근 방식에는 여러 가지 이점이 있다. 첫째, 타사 응용 프로그램에 대한 개방성과 상관없이 사람이 사용하는 거의 모든 소프트웨어와 RPA를 통합할 수 있다. 많은 기업의 IT 시스템은 공통적으로 적용되는 API가 많지 않음으로 독점적이며 다른 시스템과의 통신 기능이 크게 제한되나 RPA는 이 문제를 해결한다. 둘째, RPA는 매우 짧은 시간 내에 구현될 수 있다. 엔터프라이즈 소프트웨어 통합과 같은 전통적인 소프트웨어 개발 방식은 상대적으로 많은 시간이 소요되지만 RPA는 2~4주의 상대적으로 짧은 시간에 구현할 수 있다. 셋째, 소프트웨어 로봇을 통해 자동화된 프로세스는 시스템 사용자가 쉽게 수정할 수 있다. 기존 방식은 작동 방식을 크게 수정하기 위해 고급 코딩 기술이 필요한 반면에 RPA는 상대적으로 단순한 논리 문장을 수정하거나 인간이 수행하는 프로세스의 화면 캡처 또는 그래픽 프로세스 차트 수정을 통해 지시받을 수 있다. 이로 인해 RPA는 매우 다양하고 유연하다. 이러한 RPA는 기업에서 추구하는 D2I(Digital to Intelligence)의 좋은 적용 사례이다.