• Smart Structures and Systems
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• v.29 no.1
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• pp.251-266
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• 2022

Structural Health Monitoring (SHM) of critical infrastructure comprises a major pillar of maintenance management, shielding public safety and economic sustainability. Although SHM is usually associated with data-driven metrics and thresholds, expert judgement is essential, especially in cases where erroneous predictions can bear casualties or substantial economic loss. Considering that visual inspections are time consuming and potentially subjective, artificial-intelligence tools may be leveraged in order to minimize the inspection effort and provide objective outcomes. In this context, timely detection of sensor malfunctioning is crucial in preventing inaccurate assessment and false alarms. The present work introduces a sensor-fault detection and interpretation framework, based on the well-established support-vector machine scheme for anomaly detection, combined with a coalitional game-theory approach. The proposed framework is implemented in two datasets, provided along the 1st International Project Competition for Structural Health Monitoring (IPC-SHM 2020), comprising acceleration and cable-load measurements from two real cable-stayed bridges. The results demonstrate good predictive performance and highlight the potential for seamless adaption of the algorithm to intrinsically different data domains. For the first time, the term "decision trajectories", originating from the field of cognitive sciences, is introduced and applied in the context of SHM. This provides an intuitive and comprehensive illustration of the impact of individual features, along with an elaboration on feature dependencies that drive individual model predictions. Overall, the proposed framework provides an easy-to-train, application-agnostic and interpretable anomaly detector, which can be integrated into the preprocessing part of various SHM and condition-monitoring applications, offering a first screening of the sensor health prior to further analysis.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.295-304
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• 2006

Residual materials such as veterinary drugs, environmental contaminants, and pesticides are affecting food safety. High resolution techniques and quality controls are needed to analyze these materials from part per million to part per trillion quantities in food. In order to achieve quality results, standardized methods and techniques are required. Our laboratories were prepared to obtain a certificate of accreditation for ISO/IEC 17025 in the analytical criteria of animal drugs, dioxins, pesticides, and heavy metals. ISO together with IEC has built a strategic partnership with the World Trade Organization with the common goal of promoting a free and fair global trading system. ISO collaborates with the United Nations Organization and its specialized agencies and commissions, particularly those involved in the harmonization of regulations and public policies including the World Health Organization and CODEX Alimentarius for food safety measurement, management and traceability. Our goal was to have high quality analysts, proper analytical methods, good laboratory facilities, and safety systems within guidelines of ISO/IEC 17025. All staff members took requirement exams. We applied proficiency tests in the analysis of veterinary drugs (nitrofuran metabolites, sulfonamide and tetracyclines), dioxins, organophosphorus pesticides, and heavy metals (Cd, Pb, As) to the Food Analysis Performance Assessment Scheme (FAPAS) at Central Science Laboratory, Department for Environment Food and Rural Affairs (DEFRA), England. The results were very satisfactory. All documents were prepared, including system management, laboratory management, standard operational procedures for testing, reporting, and more. The criteria encompassed the requirements of ISO/IEC 17025:1999. Finally, the Korea Laboratory Accreditation Scheme (KOLAS) accredited our testing laboratories in accordance with the provisions of Article 23 of the National Standards Act. The accreditation will give us the benefit of becoming a regional reference laboratory in Asia.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.635-641
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• 2016

In order to drive a hybrid propulsion device which combines an engine and an electric propulsion unit, battery packs that contain dozens of unit cells consisting of a lithium-based battery are used to maintain the power source. Therefore, it is necessary to more strictly manage a number of battery cells at any given time. In order to manage battery cells, generally voltage, current, and temperature data under load condition are monitored from a personal computer. Other important elements required to analyze the condition of the battery are the internal resistances that are used to judge its state-of-health (SOH) and the open-circuit voltage (OCV) that is used to check the battery charging state. However, in principle, the internal resistances cannot be measured during operation because the parallel equivalent circuit is composed of internal loss resistances and capacitance. In most energy storage systems, battery management system (BMS) operations are carried out by using data such as voltage, current, and temperature. However, during operation, in the case of unexpected battery cell failure, the output voltage of the power supply can be changed and propulsion of the hybrid vehicle and vessel can be difficult. This paper covers the implementation of a high safety battery management system (HSBMS) that can estimate the OCV while the device is being driven. If a battery cell fails unexpectedly, a DC power supply with lithium iron phosphate can keep providing the load with a constant output voltage using the remainder of the batteries, and it is also possible to estimate the internal resistance.

• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.1-7
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• 2009

The purpose of this study was to evaluate the legibility of one-syllable Korean characters with the participation of sixteen subjects. The experiment considered nine factors including age (young and old), gender (male and female), illuminance (150lx and 600lx), viewing distance (50cm and 200cm), material type (paper and LCD), typeface (Ming and Gothic), thickness (plain and bold), color contrast (black letter/white background and white letter/black background), and complexity (simple, complex, and number) to examine main effects with a $2^{6-3}\times3$ fractional factorial design. The dependent variables were minimum character size of 100% correctness, maximum character size of 0% correctness, and minimum character size of comfortable reading preference. The results of analysis of variance (ANOVA) revealed that age, illuminance, viewing distance and complexity were significant for all dependent variables, except gender which was significant only for the minimum character size of comfortable reading preference. In general, the young could see twofold smaller size letters than the elderly. The subjects could see smaller sized letters with the illuminance of 600lx and viewing distance of 50cm than 150lx and 200cm, respectively and also with numbers, simple characters, and complex characters in that order. The findings of this study could be characterized about the legibility of Korean characters and be good resources for developing its standard.

• Journal of Food Hygiene and Safety
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• v.38 no.1
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• pp.12-18
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• 2023

Beef traceability systems help prevent the distribution of Hanwoo (Korean native cattle) meat as imported beef. In particular, assigning a traceability number to each cattle can provide all information regarding the purchased Hanwoo meat to the consumers. In the present study, a DNA identity test was conducted on 344 samples of Hanwoo meat from large livestock product stores in Seoul between 2021 and 2022 to determine the authenticity of important label information, such as the traceability number. Traceability number mismatch was confirmed in 45 cases (13.1%). The mismatch rate decreased to 11.3% in 2022 from 14.7% in 2021, and the mismatch rate was higher in the northern region (16.9%) than in the southern region (10.2%). In addition, of the six brands, B and D showed satisfactory traceability system management, whereas E and A showed poor traceability system management, with significant differences (P<0.001). The actual traceability number confirmation rate was only 53.9% among the mismatch samples. However, examination of the authenticity of label information of the samples within the identified range revealed false marking in the order of the traceability number (13.1%), sex (2.9%), slaughterhouse name (2.2%), and grade (1.6%); no false marking of breed (Hanwoo) was noted. To prevent the distribution of erroneously marked livestock products, the authenticity of label information must be determined promptly. Therefore, a legal basis must be established mandating the filling of a daily work sheet, including the traceability number of beef, in partial meat subdivisions. Our findings can be used as reference data to guide the management direction of traceability systems for ensuring transparency in the distribution of livestock products.

• Korean Journal of Clinical Pharmacy
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• v.33 no.1
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• pp.22-34
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• 2023

Background: With the increasing use of narcotic analgesics, the Ministry of Food and Drug Safety has been operating the National Narcotics Information Management System (NIMS) since 2018 in Korea. Some studies are related to the narcotic analgesics use, but the evaluation studies of system, including NIMS users are insufficient. Objective: This study evaluated the NIMS enforcement process through in-depth interviews on the experience of using NIMS of doctors and pharmacists who prescribe or dispense opioid analgesics. Methods: Participants in this study were selected through purposeful sampling as three doctors and two pharmacists in the metropolitan area. The interviews were conducted from August 27 to October 19, 2022. Each interview was analyzed using a phenomenological method. Results: Six components of this study included "Doctors and pharmacists come across drug abusers", "They respond individually to drug abusers", "They use NIMS tailored to the needs of system managers", "They are concerned about the role of NIMS in practice settings", "They face challenges against drug abusers" and "They find a way to utilize the system to deal with drug abusers." The interviews confirmed that doctors and pharmacists used NIMS little in their work, and they only reported data. Therefore, it might be difficult for doctors and pharmacists to take measures for the safe use of narcotic analgesics. Conclusion: It is likely that adding data-feedback and medication-check function can reduce the abuse of narcotic analgesics. In the future, further studies on the evaluation of the empirical results of NIMS and review of systems in other countries will be required.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.13-21
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• 2023

In the recent era of the fourth industrial revolution, many industries aim to maximize the efficiency of products and services by introducing cutting-edge technologies such as artificial intelligence and big data. In this situation, organizational culture is changing a lot due to the influx of the MZ generation with strong individualistic tendencies and the decreased face-to-face communication between members. However, active communication with colleagues is still essential to maximize performance, and the margins created by simplifying work processes and automating processes must be used for creating work performance. This requires cooperation and commitment through the job immersion of members who have an active attitude. This study analyzed how the organization's autonomous work environment and trust among members, which are creative work performance conditions, affect job immersion using raw data from the Occupational Safety and Health Research Institute. As a result, it was found that both the organization's autonomous working environment and trust among members significantly effected the members' job immersion. in order to achieve productivity and value improvement in companies, efforts are needed to increase workers' job immersion by building an autonomous working environment and trust among members. The results of this study are expected to contribute significantly to the search for ways to increase workers' job commitment to improve organizational productivity.

• Journal of the Korean Society of Visualization
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• v.20 no.1
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• pp.45-51
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• 2022

Airborne particulate matter(PM) has been a global environmental problem. PM whose diameter is smaller than 10 ㎛ can permeate respiratory organs and has harmful effects on human health. Therefore, PM monitoring systems are necessary for management of PM and prevention of PM-induced negative effects. Conventional PM monitoring techniques are expensive and cumbersome to handle. In the present study, two types of PM monitoring devices were designed for measuring indoor PM concentration, portably. We experimentally investigated the performance of three commercial PM concentration measurement sensors in a closed test chamber. As a result, PM2008 sensor showed the best PM concentration measurement accuracy. Linear regression method was applied to convert PM concentration value acquired from PM2008 sensor into ground truth value. A mobile application(app.) was also created for users to check the PM concentration, easily. The mobile app. also provides safety alarm when the PM₁₀ concentration exceeds 81 ㎛/m³. The developed hand-held system enables the facile monitoring of surrounding air quality.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.550-561
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• 2019

Objectives: The purpose of this study is to provide basic data for the improvement of the working environment for health prevention and related countermeasures for shift workers. This study was conducted based on the Fifth Korean Working Conditions Survey (KWCS), which analyzed the health effects of shift work forces and compared them with preceding studies. Methods: By analyzing secondary rates using raw data from the 5th KWCS, 4,870 (9.7%) of the 50,184 total study subjects were divided into shift work and 45,314 (90.3%) non-shift work groups based on the response to shift status. Variables that could affect work health issues were identified and corrected. A cross-analysis was conducted to examine demographic characteristics (gender, age, and education level) of the workers and occupation characteristics (monthly net earnings, employment type, occupation, working period up to now, workplace scale, type of work system, and weekly working hours). In order to find the work health issue ratio between the shift and non-shift work groups, logistic regression was analyzed and the association with health problems according to shift type by gender was looked at through cross-analysis. Results: According to the surveys conducted from the 1st KWCS (2006) to the 5th KWCS (2017), the proportion of shift workers continued to increase. Also, muscular pains in the lower limbs (hips, legs, knees, feet, etc.) (OR=1.135, 95%CI 1.031-1.251), headaches, eyestrain (OR=1.580, 95% CI 1.428-1.748), anxiety (OR=1.715, 95% CI 1.402-2.099), difficulty falling asleep (OR=1.391), and other problems (OR=7.392) were reported. In addition, back pain, muscular pains in shoulders, neck and/or upper limbs, muscular pains in lower limbs (hips, legs, knees, feet, etc.), headaches, eyestrain, depression, anxiety, overall fatigue resulted in significant results for both male and female shift workers. Depression and anxiety were higher in female shift/circulation compared to males. Conclusions: The social nets for the health and safety of shift workers should be explored in a variety of ways, including management and supervision of shift sites, attempts to reorganize and improve the shift system, development of workers' health recovery programs, promotion, systematic treatment, and compensation systems.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.835-842
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• 2022

Several countries are establishing management systems for aquaculture environment, and fishery environment assessment is one of them. The fishery management law amended in 2013 stipulates that a fishery environment assessment should be performed when a fish cage farm's license is extended. The purpose of the fishery environment assessment is to promote sustainable fishery, increase the fishery production capacity, and increase the fishermen incoming by implementing evaluation and improvement measures through scientific methods. The analysis items of fishery environment assessment include the Benthic Health Index (BHI), which is a biological index based on the macrobenthic polychaetes community, and total organic carbon (TOC), and the two items are scored and used for evaluation as a single grade. This study explains the selection process of BHI and TOC, which are evaluation items for fishing ground, and ecological significance of the calculated evaluation grades.