• 한국수산과학회지
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• 제51권2호
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• pp.121-126
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• 2018

The purpose of this study was to assess bacteriological hazards in the following 7 kinds of minimally processed shellfish products purchased from Korean seafood retail outlets: raw oysters stored with seawater in polyethylene bags, frozen oysters, raw mussels, frozen mussels, boiled mussels, raw short-necked clam, and frozen short-necked clams, obtained from Korean seafood retail outlets. The total coliform and Escherichia coli counts determined in all samples were detected below regulation limit of the Korean government guidelines (Food Code). In addition, the high-risk bacterial pathogens, Listeria monocytogenes, Salmonella spp., and E. coli O157:H7 were not detected in any samples. Low-risk pathogens such as Staphylococcus aureus and Vibrio parahaemolyticus were detected at levels above $1.0{\times}10^2$ colony forming unit (CFU)/g in some minimally processed shellfish products. Notably, S. aureus was detected in all samples. Raw oysters stored with seawater in polyethylene bags, frozen oysters, and boiled blue mussels are commonly ingested without heating, and therefore these minimally processed shellfish products pose bacteriological hazards. The detection of S. aureus in all shellfish products, an organism indicative of poor personal hygiene, which can grow and multiply during distribution, indicates the necessity of improving the food safety of minimally processed shellfish products.

• 한국수산과학회지
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• 제52권1호
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• pp.19-26
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• 2019

The objective of this study was to analyze bacteriological and chemical hazards in minimally processed commercial fish products, including Hwangtae (freeze-dried pollock), dried anchovy, fermented anchovy sauce, and salted and dried yellow croaker. Escherichia coli counts from all samples were below the regulation limits of the Korean Ministry of Food and Drug Safety Standards on Quality of Seafood and Seafood Products (Food Code). However, the food poisoning bacterium Staphylococcus aureus was detected at levels above $1.0{\times}10^2$ colony forming units (CFU)/g in Hwangtae, dried anchovy, and salted and dried yellow croaker, which are commonly ingested without heating and pose bacteriological hazards. The detection of S. aureus, an organism indicative of poor personal hygiene, which can be introduced by employees and multiply during distribution, indicates the necessity of improving the sanitary control of minimally processed commercial fish products. Histamine was not detected from dried anchovy or salted and dried yellow croaker, but was detected at some of the highest levels in fermented anchovy sauces. This result suggests that efforts to reduce the amount of histamine in fermented anchovy sauces are required.

• Smart Structures and Systems
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• 제6권4호
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• pp.405-421
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• 2010

This paper proposes a method for early warning of hazard for pipelines. Many pipelines transport dangerous contents so that any damage incurred might lead to catastrophic consequences. However, most of these damages are usually a result of surrounding third-party activities, mainly the constructions. In order to prevent accidents and disasters, detection of potential hazards from third-party activities is indispensable. This paper focuses on recognizing the running of construction machines because they indicate the activity of the constructions. Acoustic information is applied for the recognition and a novel pipeline monitoring approach is proposed. Principal Component Analysis (PCA) is applied. The obtained Eigenvalues are regarded as the special signature and thus used for building feature vectors. One-class Support Vector Machine (SVM) is used for the classifier. The denoising ability of PCA can make it robust to noise interference, while the powerful classifying ability of SVM can provide good recognition results. Some related issues such as standardization are also studied and discussed. On-site experiments are conducted and results prove the effectiveness of the proposed early warning method. Thus the possible hazards can be prevented and the integrity of pipelines can be ensured.

• Computers and Concrete
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• 제3권2_3호
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• pp.123-144
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• 2006

Reinforced concrete corbels are structural elements widely used in practical engineering. The complex response of these elements is described in design codes in a simplified manner. These formulations are not sufficient to show the real behavior, which, however, is an essential prerequisite for the manufacturing of numerous elements. Therefore, a deterministic and probabilistic study has been performed, which is described in this contribution. Real complex structures have been modeled by means of the finite element method supported primarily by experimental works. The main objective of this study was the detection of uncertainties effects and safety margins not captured by traditional codes. This aim could be fulfilled by statistical considerations applied to the investigated structures. The probabilistic study is based on advanced Monte Carlo simulation techniques and sophisticated nonlinear finite element formulations.

• 한국전기전자재료학회논문지
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• 제31권6호
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• pp.427-432
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• 2018

High-capacity secondary batteries can cause explosion hazards owing to microcurrent variations or current surges that occur in short circuits. Consequently, complete safety cannot be achieved with general protection that is limited to a mere current fuse. Hence, in the case of secondary batteries, it is necessary for the protector to limit the inrush current in a short circuit, and to detect the current during microcurrent variations. To serve this purpose, a fuse can be employed for the secondary battery protection circuit with current detection. This study aims at designing a protection device that can stably operate in the hazardous circumstances associated with high-capacity secondary batteries. To achieve the said objective, a detecting fuse was designed from an alloy of low melting point elements for securing stability in abnormal current states. Experimental results show that the operating I-T and V-T characteristic constraints can be satisfied by employing the proposed current detecting self-contained low melting point fuse, and through the resistance of the heating resistor. These results thus verify that the proposed protection device can prevent the hazards of short circuit current surges and microcurrent variations of secondary batteries.

• 한국정밀공학회지
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• 제28권11호
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• pp.1330-1338
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• 2011

Social activities of the elderly have been increasing as our society progresses toward an aging society. As their activities increase, so does the occurrence of falls that could lead to fractures. Falls are serious health hazards to the elderly. Therefore, development of a device that can detect fall accidents and prevent fracture is essential. In this study, we developed a portable fall detection system for the fracture prevention system of the elderly. The device is intended to detect a fall and activate a second device such as an air bag deployment system that can prevent fracture. The fall detection device contains a 3-axis acceleration sensor and two 2-axis tilt sensors. We measured acceleration and tilt angle of body during fall and activities of daily(ADL) living using the fall detection device that is attached on the subjects'. Moving mattress which is actuated by a pneumatic system was used in fall experiments and it could provide forced falls. Sensor data during fall and ADL were sent to computer and filtered with low-pass filter. The developed fall detection device was successful in detecting a fall about 0.1 second before a severe impact to occur and detecting the direction of the fall to provide enough time and information for the fracture preventive device to be activated. The fall detection device was also able to differentiate fall from ADL such as walking, sitting down, standing up, lying down, and running.

• 한국항행학회논문지
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• 제23권6호
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• pp.495-500
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• 2019

FOD (foreign object debris)는 각종 금속 및 비금속 이물질 및 항공기 운항에 잠재적 위험요소를 가진 물질을 총칭한다. 항공기 이동지역에서 사람이 직접 FOD 탐지 및 수거를 하던 방식은 효율성 및 경제성 또한 매우 낮기 때문에 국내환경에 적합한 FOD 자동 탐지 시스템 개발이 필수적으로 요구된다. 본 논문에서는 한서대학교 태안비행장에서 EO/IR카메라 및 레이더를 이용한 고정형 이물질 자동 탐지 시스템과 이동형 이물질 자동 탐지 시스템을 이용하여 100 m이상 최적탐지시간과 90% 탐지 정확도의 복합운영을 위한 두 시스템의 성능비교 실험 결과이다. 지속적인 연구개발을 통하여 FOD를 무인력으로 수행 할 수 있을것으로 기대된다.

• 한국정보전자통신기술학회논문지
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• 제16권4호
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• pp.210-219
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• 2023

농촌 인구의 감소와 고령화로 인한 노동력 부족, 비닐하우스 내의 악화된 환경과 위험에 따른 사망 사례가 발생하고 있다. 이에 따라, 비닐하우스에서의 작물 재배와 병해 검출을 자동화하여 인력 손실을 막는 시스템이 필요하다. 본 논문에서는 비닐하우스에서 작물의 병해를 검출하기 위해 객체 검출 기반의 모델을 활용한다. 또한, 클라우드에서 인공지능 모델의 환경을 구성하여 안정성을 확보한다. 제안하는 시스템은 비닐하우스 내에서 촬영한 영상을 데이터베이스에 저장하고, 클라우드에서 영상을 다운로드한 후 Yolo-v4를 기반으로 추론한 검출 결과를 JSON 파일로 생성한다. 이 파일을 분석하여 데이터베이스로 전송하여 저장한다. 실험 결과로 객체 검출을 통한 병해 감지는 비닐하우스와 같은 실제 환경에서 높은 성능을 나타냄을 확인할 수 있고 데이터베이스를 통하여 효율적인 모니터링이 가능함을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1301-1305
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• 2006

The development of rapid, infallible, and sensitive methods of detecting foodborne pathogens has received much impetus in recent years owing to an increased public awareness of the health hazards. For the rapid and simultaneous detection of these foodborne pathogens, a multiplex PCR method was developed. Yersinia enterocolitica, Staphylococcus aureus, and Shigella spp. are bacteria of concern because of their specific growing condition that enables them to live at low temperatures. In order to detect each pathogenic bacterium, specific primers from Y. enterocolitica, St. aureus, and Sh. flexneri were selected and validated successfully. To apply this method to food stored at low temperature, Y. enterocolitica, St. aureus, and Sh. flexneri were artificially inoculated in lettuce and incubated for enrichment. The multiplex PCR assays were able to simultaneously detect three pathogens, and the presence of three bands was observed at initial inoculation levels of approximately 1$\times$10$^1$ CFU/g in lettuce. Therefore, this method could be used for simultaneous detection of Y. enterocolitica, St. aureus, and Shigella spp. contaminated in lettuce during cultivation, transportation, preservation, and storage.

• 조명전기설비학회논문지
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• 제27권11호
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• pp.27-36
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• 2013

Islanding in a gird connected inverter of wind power generation system may influence a bad effect on equipments or yield safety hazards on grid so it should be detected rapidly and exactly. A passive method to detect islanding is comparatively simpler than an active method but suffers from non detection zone (NDZ). On the other hand, the active method can significantly reduce NDZ by injecting a disturbance into inverter output. To improve the reliability of islanding detection, this paper proposes a hybrid anti-islanding detection method combining the conventional passive method as well as the active method based on novel harmonic injection method using fourier transform. The proposed scheme is fast to detect islanding when NDZ does not exist because it has the nature of passive method. Under NDZ, the active method can detect occurrence of islanding reliably. The effectiveness and validity of the proposed scheme is proved through comparative simulations.