• Nuclear Engineering and Technology
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• 제45권6호
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• pp.791-794
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• 2013

Since the Fukushima accident in 2011, the importance of the electrical systems in nuclear power plants (NPPs) has been emphasized. The result has been that NPP regulators are enhancing their monitoring of loss of offsite power (LOOP) events. Korea Hydro & Nuclear Power Co. (KHNP) is reviewing the status and issues related to LOOPs, and is attempting to establish specific countermeasures to prevent LOOPs, because they can have severe consequences in the complicated maintenance schedule during an outage. A starting point for preventing LOOPs is the control of the loss of voltage (LOV)-initiating components. In order to reflect this in the risk assessment program, an LOV monitor is being developed for use during plant outages.

• 한국연소학회지
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• 제6권1호
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• pp.14-19
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• 2001

Interests and importance of down-scale combustor is increasing with the emerging need for miniaturized power source which is now a bottleneck of micro system development. But in down scaled combustor increased heat loss compared to thermal energy generation inhibits the usability and application of the device, so as a preliminary work of down scaled combustor fabrication. Modeling tool for the device should be established, in this study modeling approach of closed vessel combustion phenomena that can express heat loss effect and resulting quenching is proposed and the result is compared with experiment data. From this model heat loss effect following combustor scale down can be further understood, and further more design parameter and analysis tool can be obtained.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 춘계학술발표대회
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• pp.472-474
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• 2019

Because of the difference in network structure and loss function, Verification and identification models have their respective advantages and limitations for person reidentification (re-ID). In this work, we propose a multi-task network simultaneously computes the identification loss and verification loss for person reidentification. Given a pair of images as network input, the multi-task network simultaneously outputs the identities of the two images and whether the images belong to the same identity. In experiments, we analyze the major factors affect the accuracy of person reidentification. To address the occlusion problem and improve the generalization ability of reID models, we use the Random Erasing Augmentation (REA) method to preprocess the images. The method can be easily applied to different pre-trained networks, such as ResNet and VGG. The experimental results on the Market1501 datasets show significant and consistent improvements over the state-of-the-art methods.

• 한국건축시공학회지
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• 제10권4호
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• pp.123-132
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• 2010

Rebar work accounts for approximately 30% of the total construction costs for rebars and concrete. Recently, the high rising prices of rebars have become one of the principle factors of rising construction costs. Therefore, construction companies are putting much effort into loss reduction of rebars. Consequently, in this study, we wished to present loss reduction methods of rebars before the preparation of the placing drawings. To devise such methods, we collected previous case studies and analyzed methods that were applied for loss reduction. As a result of the analysis, we were able to find the following methods for loss reduction of rebars: method of reducing the number of splices at the mat foundation, method of reducing splice length at the internal columns or walls of the underground parking lot, method of reducing cap-ties of internal beams of basement floors excluding perimeter beams, and method of reducing anchorage length at the internal column or wall of the underground parking lot. Based on those analysis results, we presented our own loss reduction methods of rebars. Applying our methods resulted in considerable loss reduction.

• 한국전기전자재료학회논문지
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• 제16권5호
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• pp.418-423
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• 2003

AC loss is an important issue in the design of high-T$\sub$c/ superconducting power cables which consist of a number of Bi-2223 tapes wound on a former. In the cables, the tapes have different critical currents intrinsically. And they are electrically connected to each other and current leads. These make loss measurements considerably complex, especially for short samples of laboratory size. So special cautions are required in the positioning of voltage leads for measuring the true loss voltage. In this work we have prepared a conductor composed of three Bi-2223 tapes with different critical currents. The critical current and AC loss characteristics in the conductor have experimentally investigated. The results show that for uniform current distributions the conductor's critical current is proportional to the critical current of the Bi-2223 tape to which a voltage lead is attached. However it depends on the current non-uniformity parameter in the conductor rather than the tape's critical currents for nonuniform current distributions. The loss tests indicate that the AC loss is dependent on arrangements of voltage leads but not on their contact positions. The measured losses in the conductor also agree well with the sum of the transport losses measured in each Bi-2223 tape.

• Structural Engineering and Mechanics
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• 제88권1호
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• pp.13-23
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• 2023

Seismic risk assessment studies are one of the most crucial instruments for mitigating casualties and economic losses. This work utilizes fragility curves to evaluate the seismic risk of single-story precast buildings, which are generally favored in Marmara's organized industrial zones. First, the precast building stock in the region has been categorized into nine sub-classes. Then, seven locations in the Marmara region with a high concentration of industrial activities are considered. Probabilistic seismic hazard assessments were conducted for both the soil-dependent and soil-independent scenarios. Subsequently, damage analysis was performed based on the structural capacity and mean fragility curves. Considering four different consequence models, 630 sub-class-specific loss curves for buildings were obtained. In the current study, it has been determined that the consequence model has a significant impact on the loss curves, hence, average loss curves were computed for each case investigated. In light of the acquired results, it was found that the loss ratio values obtained at different locations within the same region show significant variation. In addition, it was observed that the structural damage states change from serviceable to repairable or repairable to unrepairable. Within the scope of the study, 126 average loss functions were presented that could be easily used by non-experts in earthquake engineering, regardless of structural analysis. These functions, which offer loss ratios for varying hazard levels, are valuable outputs that allow preliminary risk assessment in the region and yield sensible outcomes for insurance activities.

• 한국건축시공학회지
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• 제23권6호
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• pp.875-885
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• 2023

This research delves into the evolving interplay between occupational diseases, work-related illnesses, and accidents in the construction industry, focusing on the past twenty years. One significant discovery is the 19-fold escalation in reported occupational diseases, prompting an examination of their root causes and connections to workplace environments. Frequently encountered work-related ailments include physically strenuous tasks, low back pain, and cerebrovascular issues, highlighting the need for robust prevention and management approaches. Predominantly, noise-induced hearing loss and pneumoconiosis are the most common occupational diseases. The study unveils notable correlations between specific work-related illnesses and accidents, indicating the necessity for bespoke safety measures. Additionally, a pronounced association between work-related illnesses and occupational diseases offers insights into underlying risk factors. Remarkably, the findings propose a bidirectional link between occupational diseases and accidents, challenging traditional beliefs about causality. These insights are pivotal for enhancing safety protocols, focusing on preventive measures, and foreseeing occupational diseases that may arise following accidents in the construction industry.

• 한국의류학회지
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• 제30권8호
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• pp.1323-1332
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• 2006

Lyocell is a regenerated cellulose fiber manufactured by an environmentally-friendly process. Since the fiber has more crystalline region compared to rayon, lyocell shows higher wet-strength than rayon. Although fibril generation of lyocell is lower than that of rayon because of the reason, the fibril generated during the wet process deteriorates the smooth look and soft touch of the fabric. The efficient way to remove the fibril yet retain the strength property was investigated in this work. In order to scour and remove the fibril from the fabric, cellulase enzymes were introduced and the traditional scouring was carried to be compared. Weight loss, dye-ability, and strength of treated fabric were measured after the treatments. Scanning electron microscopy was used to observe the surface of the fiber. Among the cellulases used in this work, Denimax 992L showed the best results for removal of fibril with low weight loss and tensile strength loss. The optimal conditions for the enzymatic treatment could be chosen depending on a characteristic for final purpose of the lyocell product.

• 천문학회보
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• 제37권2호
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• pp.122-122
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• 2012

Geosynchronous electron flux dropouts are most likely due to fast drift loss of the particles to the magnetopause (or equivalently, the "magnetopause shadowing effect"). A possible effect related to the drift loss is the radial diffusion of PSD due to gradient of PSD set by the drift loss effect at an outer L region. This possibly implies that the drift loss can affect the flux levels even inside the trapping boundary. We recently investigated the details of such diffusion process by solving the diffusion equation with a set of initial and boundary conditions set by the drift loss. Motivated by the simulation work, we have examined observationally the energy spectrum and pitch angle distribution near trapping boundary during the geosynchronous flux dropouts. For this work, we have first identified a list of geosynchronous flux dropout events for 2007-2010 from GOES satellite electron measurements and solar wind pressures observed by ACE satellite. We have then used the electron data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft measurements to investigate the particle fluxes. The five THEMIS spacecraft sufficiently cover the inner magnetospheric regions near the equatorial plane and thus provide us with data of much higher spatial resolution. In this paper, we report some case studies showing energy dependence during magnetopause shadowing effect.

• 한국환경보건학회지
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• 제17권2호
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• pp.48-53
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• 1991

This study was carried out to investigate age, noise intensity, work period, hearing loss at frequencies, hypertension and to examine correlation of the total quantity of noise exposure(Dose) and blood pressure (Response) in the auto industry during May 1987-December 1987. To perform this study 65 workers were tested. Results of this study were as follows: 1. In frequency analysis, the CS-dip phenomenon occurred around 4000 Hz. 2. Between under of ten years group and over of ten years group, average hearing loss value was statitically significant (P < 0.05). 3. The prevalence of hypertension of 65 workers was 7.84% . 4. At 90dB(A) over and 10 years under and workers in the 20's group, the total quantity of noise exposure (Dose) and systolic blood pressure (Response) were statistically significant (P < 0.05). 5. At under 10 years of work period group, the total quantity of noise exposure(Dose) and diastolic blood pressure (Response) were statistically significant(r =0.234, P < 0.1).