• Journal of Korean Society for Atmospheric Environment
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• v.30 no.4
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• pp.327-338
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• 2014

The objective of this study is to enhance the effectiveness of Korean Inspection and Maintenance (I/M) program. Three main tasks are: to measure pollutant emissions of in-use light-duty diesel vehicles (LDVs); to evaluate the validity of existing smoke control scheme for low-smoke-emitting vehicles, which have diesel particulate filters, DPF, to meet stringent Euro-5 emission limits; and to assess the necessity and the benefit of $NO_x$ inspection, which is not involved in current I/M program. We measured second-by-second smoke, particulate and gaseous emissions of 27 LDVs using opacity smoke meter, photo-acoustic soot sensor, and portable emissions measurement system, respectively, under the Korean I/M test driving cycle, KD-147. We find that the DPF plays a key role in controlling soot, which can be considered as black carbon contained in particulate matter. Thus, from an I/M perspective, we believe smoke inspection strategies for Euro-5 diesel vehicles should be more focused on the capability of detecting DPF malfunctions or failures, in order to keep DPF properly functional. Fleet averaged distance-specific $NO_x$ emissions are consistently higher than corresponding emission limits, and the values are similar among pre-Euro-3, Euro-3, and Euro-4 vehicle fleets. These findings indicate that the $NO_x$ inspection should be incorporated into current I/M program in order to manage urban $NO_x$ emissions. This research allows the Korean I/M program keep pace with developments in vehicle technologies, as well as the increased emphasis on $NO_x$ with respect to air quality and human health.

• Convergence Security Journal
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• v.14 no.4
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• pp.85-94
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• 2014

Information Security Check System was Introduced in 2004, higher than in 2013, the effectiveness of Information Security Management System(ISMS) certification scheme was to unification. This is incident to the Internet affecting people's lives telecommunications service provider to target accountability because, considering the subject's duty selection criteria need to be clarified. however, Obligations under the current legislation, subject selection criteria applying the law itself is ambiguous, the result being a significant problem. Moreover, the regulatory system of certification systems subjects, although selection criteria should be clear and objectively not the obligation not to distrust the system itself and the subject was raised many issues for you. In this study, with SMART Technic in order to improve this certification you can easily determine whether a medical person authorized to develop a model for selection of medical subjects, The developed model is verified through empirical ways to improve the system by presenting the system to help, to secure the effectiveness.

• Convergence Security Journal
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• v.15 no.6_1
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• pp.3-16
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• 2015

Ten years have passed since an arm-college joint education system with the goal of efficiently acquiring future non-commissioned officers (NCOs), and approximately 4,000 annual graduates of the programs have already actively been in position in Korean Army. We evaluated the effectiveness of the system based on an empirical survey for 100 respondents, all sergeants-first-class and above. The analysis shows that the graduates' general performance and attitude as NCOs appear to be superior to those who were recruited from the general public, while there were no statistically significant difference in some other areas. NCOs from the departments of the program showed higher capacity to conduct his duty of expertise, better accountability, and more positive attitude toward the routine tasks. Several policy messages are also drawn. We suggest that the Army and the relevant schools take appropriate measures like more active institutional support for upgrading the system. Additionally, their initial selection process for prospective NCOs, high school graduates, should also be improved.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.23-30
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• 2009

A new high performance and low cost unified power system is proposed through investigating conventional Power-Integrated Drive(PID) system and Power-Separated Drive(PSD) system applied to LCD TV. Since the proposed system consists of two stage, namely power and inverter stage it features high efficiency and cost effectiveness. To satisfy the safety standard of the High voltage transformer, 1:1 transformer is employed between inverter and high voltage transformer. Moreover, to ensure the Zero Voltage Switching(ZVS) of all power switches and the Pulse Count Modulation(PCM) method is employed, which controls the number of pulse at the fixed frequency and fixed duty cycle. Therefore, it features high efficiency, improved heat generation, cost effectiveness and good EMI performance including no additional current balancing coil. To confirm the validity of proposed system, comparison of conventional system, verification of experimental results are presented.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.55-61
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• 2023

Although corporate punishment-related systems are being implemented in several countries, such as South Korea's Serious Accidents Punishment Act (SAPA), related research has mainly focused on legal issues. This study aimed to compare and analyze the SAPA and Singapore's Workplace Safety and Health Act (WSHA) and Code of Practice on Chief Executives' and Board of Directors' Workplace Safety and Health Duties (WSHD). In addition, it was attempted to draw implications to enhance the effectiveness of the CEO's safety and health duties. For this study, a comparative analysis was conducted in 3 steps. In step 1, similar overseas systems were investigated. In step 2, the system contents were classified into four viewpoints (DUTY, RESOURCE, Other factors, and Main contents), and comparison items were derived from each viewpoint. In step 3, the viewpoints were compared, and implications were derived. The following three implications were derived through comparative analyses. 1) In WSHD, additional explanation and calibration of measures clarify the CEO's role, and 2) It is easy to use for the CEO's duties by providing the resources directly. 3) Penalties for violating the proposed duties are entrusted to the existing higher-level laws. Considering this, providing detailed content and related information for the CEO would possibly improve the SAPA to fulfill his/her duties through announcements from related organizations in the future.

• Journal of Power Electronics
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• v.14 no.1
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• pp.30-39
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• 2014

This paper studies a new three-level pulse-width modulation (PWM) resonant converter for high input voltage and high load current applications. In order to use high frequency power MOSFETs for high input voltage applications, a three-level DC converter with two clamped diodes and a flying capacitor is adopted in the proposed circuit. For high load current applications, the secondary sides of the proposed converter are connected in parallel to reduce the size of the magnetic core and copper windings and to decrease the current rating of the rectifier diodes. In order to share the load current and reduce the switch counts, three resonant converters with the same active switches are adopted in the proposed circuit. Two transformers with a series connection in the primary side and a parallel connection in the secondary side are adopted in each converter to balance the secondary side currents. To overcome the drawback of a wide range of switching frequencies in conventional series resonant converters, the duty cycle control is adopted in the proposed circuit to achieve zero current switching (ZCS) turn-off for the rectifier diodes and zero voltage switching (ZVS) turn-on for the active switches. Finally, experimental results are provided to verify the effectiveness of the proposed converter.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.551-556
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• 2012

Fatigue is known to detrimentally affect a person's performance. Also, fatigue may reduce effectiveness and efficiency of marine officers and crew members. The purpose of this research is to understand on the status of the marine officers' fatigue. In this study, we carried out the questionnaire survey which is related to the marine officers' fatigue factors such as work, sleep and rest hour or period, sleepiness, casual factor, fatigue symptom, etc. The questionnaire contained 25 questions and it was distributed among 1,033 marine officers(deck officers 607 and engineers 426). The results of this survey show that marine officers' fatigue is a casual factor in marine accidents such as collisions, groundings and there was a fatigue difference between deck officers and engineers.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.3
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• pp.177-184
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• 2018

In case that limited resources can be mobilized, non-structural countermeasures such as 'monitoring using Information and Communication Technology might be one of solutions to mitigate disaster risks. Having established the monitoring system, operational and maintenance costs to maximize the effectiveness might trouble the authority concerned or duty attendant who is in charge. In this respect, "Guerrilla Sensor" would be very cost effective because of the inherent mobility characteristic. The sensor device with the IRIS camera and GPS (Global Positioning System) equipped, is basically battery-operated and communicates with WCDMA (Wideband Code Division Multiple Access). It has a strong advantage of capabilities for 'Disaster Response' with immediate and prompt action on the spot, making the best use of IoT (Internet of Things), especially with the mobile web. This paper will explain how the sensor system works in real-time GIS (Geographic Information System) pinpointing the exact location of the abnormal movement/ground displacement and notifying the registered users via SMS (Short Message Service). Real time monitoring with early warning and evaluation of current situations with LBS (Location Based Service), live image and data information can help to reduce the disaster impact. Installation of Guerrilla sensor for a real site application at Gimcheon, South Korea is also reported.

• Convergence Security Journal
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• v.14 no.3_1
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• pp.3-9
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• 2014

NCOs of the amy-navy-air force are the foundation in maintaining, developing and leading the army making manpower aquisition very important. Currently, the operation or the recruitment business is being overlapped by each training institutions leading to uneffectively decreasing the curiosities of the applicants regarding their future. Even though the NCO selection policy is strong in the aspect of retaining uniqueness, use of acquired specialist, and statute revision, it is showing insufficiency in publicizing, selection effectiveness, promotion of peoples' conveniency, and budget reduction. Therefore, if the unification regarding the recruitment of each military sectors are run by the MMA(Military Manpower Administration), which is the institute that is fully responsible for the recruitment duty, it can acquire excellent man power while decreasing effort and resources, provide accurate information to the NCO applicants on time, and provide improved services through the convenient facilities and systems.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.182-192
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• 2015

This study develops a digital control scheme with power factor correction for a front-end converter in an electric vehicle battery charger. The front-end converter acts as the boost-type switching-mode rectifier. The converter assumes the two roles of the battery charger, which include power factor control and robust charging performance. The proposed control scheme consists of a charging control algorithm and a grid current control algorithm. The scheme aims to obtain unity input power factor and robust performance. Based on the linear average model of the converter, a constant-current constant-voltage charging control algorithm that passes through only one proportional-integral controller and a current feed-forward path is proposed. In the current control algorithm, we utilized a second band pass filter, a single-phase phase-locked loop technique, and a duty-ratio feed-forward term to control the grid current to be in phase with the grid voltage and achieve pure sinusoidal waveform. Simulations and experiments were conducted to verify the effectiveness of the proposed control scheme, both simulations and experiments.