• Journal of Welding and Joining
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• v.34 no.1
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• pp.21-25
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• 2016

The automotive vehicle is made through the following processes such as press shop, welding shop, paint shop, and general assembly. Among them, the most important process to determine the quality of the car body is the welding process. Generally, more than 400 pressed panels are welded to make BIW (Body In White) by using the RSW (Resistance Spot Welding) and GMAW (Gas Metal Arc Welding). Recently, as the needs of light-weight material due to the $CO_2$ emission issue and fuel efficiency, new joining technologies for aluminum, CFRP (Carbon Fiber Reinforced Plastic) and etc. are needed. Aluminum parts are assembled by the spot welding, clinching, and SPR (Self Piercing Rivet) and friction stir welding process. Structural adhesive boning is another main joining method for light-weight materials. For example, one piece aluminum shock absorber housing part is made by die casting process and is assembled with conventional steel part by SPR and adhesive bond. Another way to reduce the amount of the car body weight is to use AHSS (Advanced High Strength Steel) panel including hot stamping boron alloyed steel. As the new materials are introduced to car body joining, productivity and quality have become more critical. Productivity improvement technology and adaptive welding control are essential technology for the future manufacturing environment.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.907-916
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• 2020

This research was conducted to investigate the linear expansion and resistance properties of a composite board (com-ply). This board was made of medium-density fiberboard (MDF) laminated using avocado (Persea americana), mahogany (Swietenia mahogani), and pine (Pinus merkusii) veneers. These three types of veneers were laminated on both surfaces of the MDF using adhesives, namely, epoxy and isocyanate. Glue (250 g·m^-2) was spread on the surface, followed by cold press for 3 h with an applied pressure of 15 kg·cm^-2. The research result revealed that com-ply exhibited an increased dimensional stability compared with MDF, indicated by reduction in water absorption, thickness swelling, and linear expansion. The com-ply made of the pine veneer and isocyanate adhesive exhibited high density, water absorption, thickness swelling, and screw withdrawal load. The com-ply that exhibited the strongest resistance to drywood termite attacks was the one made of the mahogany veneer and isocyanate adhesive. Moreover, the com-ply that exhibited the biggest weight loss (3.6 %) was made of the pine veneer and epoxy adhesive. The results of this research may facilitate in manufacturing com-ply using the selected veneer and adhesive without the application of hot press.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1669-1679
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• 1996

In this paper, we address the problem of how to replace huffers in multimedia database systems with time-varying skewed data access. The access pattern in the multimedia database system to support audio-on-demand and video-on-demand services is generally skewed with a few popular objects. In addition the access pattem of the skewed objects has a time-varying property. In such situations, our analysis indicates that conventional LRU(least Recently Used) and LFU(Least Frequently Used) schemes for buffer replacement algorithm(ABRN:Adaptive Buffer Replacement using Neural suited. We propose a new buffer replacement algorithm(ABRN:Adaptive Buffer Replacement using Neural Networks)using a neural network for multimedia database systems with time-varying skewed data access. The major role of our neural network classifies multimedia objects into two classes:a hot set frequently accessed with great popularity and a cold set randomly accessed with low populsrity. For the classification, the inter-arrival time values of sample objects are employed to train the neural network.Our algorithm partitions buffers into two regions to combine the best roperties of LRU and LFU.One region, which contains the 핫셋 objects, is managed by LFU replacement and the other region , which contains the cold set objects , is managed by LRUreplacement.We performed simulation experiments in an actual environment with time-varying skewed data accsee to compare our algorithm to LRU, LFU, and LRU-k which is a variation of LRU. Simulation resuults indicate that our proposed algorthm provides better performance as compared to the other algorithms. Good performance of the neural network-based replacement scheme means that this new approach can be also suited as an alternative to the existing page replacement and prefetching algorithms in virtual memory systems.

• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.136-141
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• 2005

The K Ar ages, whole rock geochemistry and Sr Nd Pb isotopes have been determined for the submarine basalts dredged from the P2 and P3 segments of the Antarctic-Phoenix Ridge (APR), Drake Passage, Antarctica, for better understanding on temporal variation of magma chemistry in association with extinction of seafloor spreading. The fossilized APR is distant from the known hot spots, and consists of older N-MORB prior to extinction of spreading and younger E-MORB after extinction. The older N-MORB (3.5-6.4 Ma) occur in the southeast flank of the P3 segment (PR3) and the younger E-MORB (1.4-3.1 Ma) comprise a huge seamount at the P3 segment (SPR) and a big volcanic edifice at the P2 segment (PR2). The N-type PR3 basalts have higher Mg#, K/Ba, and CaO/Al2O3 and lower Zr/Y, Sr, and Na8.0 with slight enrichment in incompatible elements and almost flat REE patterns. The E-type SPR and PR2 basalts are highly enriched in incompatible elements and LREE. The extinction of spreading occurring at 3.3 Ma seems to have led to a temporal magma oversupply with E-MORB signatures. Geochemical signatures such as Ba/TiO2, Ba/La, and Sm/La suggest heterogeneity of upper mantle and formation of E-MORB by higher contribution of enriched materials to mantle melting, compared to N-MORB environment. E-MORB magmas beneath the APR seem to have been produced by low melting degree (up to 1% or more) at deeper low-temperature regime, where metasomatized veins consisting of pyroxenites have preferentially participated in the melting. The occurrence of E-MORB at the APR is a good example to better understand what kinds of magmatism would occur in association with extinction of spreading.

• Journal of Power System Engineering
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• v.21 no.6
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• pp.62-67
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• 2017

In order to achieve high efficiency of energy use and environment-friendly architectural design, various loads such as cooling, heating and hot water required by the building sector must be accurately predicted. Many studies used dynamic simulation tool to evaluate and analyze building energy performance. However, there are few studies on the comparative analysis of load results by each simulation and the evaluation of simulation characteristics and functions. In this study, the cooling, heating loads and energy demand of the buildings were evaluated using three dynamic simulations for the building with the same input conditions, and the characteristics of each simulation were compared and analyzed through the results. As a result of simulation comparative analysis, cooling, heating load and energy demand was lowest in square type and north-south direction conditions.

• Fashion & Textile Research Journal
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• v.7 no.6
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• pp.665-672
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• 2005

The purpose of this study was to assess the feasibility and the effects of near infrared lighted garments on thermo-physiological responses in human body. Seven healthy adult men were recruited for this study. All subjects were informed the contents and purpose of this study. The experiment was carried out in a climate chamber of $32^{\circ}C$, 60%RH with 'Rest', 'Exercise' and 'Recovery' period. The experimental garments consisted of briefs, undershirts(sleeveless), nightclothes, T-shirts, knee-trousers and socks. Subjects participated in two experiments, one was wearing near infrared lighted garments(NIR-O), the other was wearing regular garments(NIR-X). The order of experiment was randomized, and subjects wore experimental garments before 24 hours in order to benefit by near infrared light. Measurement items included rectal temperature ($T_{re}$), mean skin temperature ($\bar{T}_{sk}$), sweat rate, heart rate, oxygen uptake and subjective sensation. The results are as follows: As to the variation of rectal temperature and mean skin temperature, value of wearing NIR-X was higher than value of wearing NIR-O, indicating a significant level of difference (p<.001). Sweat rate under NIR-O and NIR-X condition were 575.35 g and 535.75 g, respectively. Heart rate value of NIR-X condition was higher than NIR-O. Oxygen uptake measured during experiment was the higher in NIR-X condition with significant difference (p<.001). In the subjective sensation, the value of NIR-O condition was higher than NIR-X condition without significantly difference.

• Fashion & Textile Research Journal
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• v.20 no.2
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• pp.202-209
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• 2018

This study examined thermo-physiological responses according to the design change of construction site working clothes (control (C) working clothes; prototype (P) working clothes). We measured rectal temperature, skin temperature, micro-climate within the clothes and sweat rate. In the evaluation of physiological functionality, based on pattern improvement in working clothes, P working clothes showed significantly lower rectal temperatures, trunk and thigh skin temperatures than C working clothes. It is preferable that rectal temperature should be kept low during work that is not favorable to an increase in body temperature. P working clothes were more physiologically functional than C working clothes. In addition, P working clothes showed significantly lower temperatures in the trunk and thigh parts in a micro climate temperature. We could explain that the side seam zipper on the pants and the gusset on armpit parts create an air permeability effect of lowering the temperature of micro-climate. Aggressive ventilation through the slit of the garment is an important factor for the restoration of the physiological function of the worker at rest between work. Sweat rate showed a higher level in C working clothes than P working clothes. When working in a hot environment, workwear needs to be designed so that the worker is not exposed to thermal stress. Therefore, it was evaluated that the P work clothes used in this study alleviated the physiological burdens of heat.

• Korean Institute of Interior Design Journal
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• v.26 no.4
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• pp.75-83
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• 2017

The cultural tendency based on sharing and cooperation, which has recently been a hot issue, accelerates throughout the world. This study began with a perception that a sharing culture is inherent in urban public spaces. This study aims to conduct a theoretical study of the sharing culture and to analyze the characteristics of the design composition of public spaces. This study selected squares in 16 European cities as cases for analysis. The results are summarized as follows:1)To analyze the design characteristics of public spaces in which a sharing culture is inherent, this study drew the shape and type of planes and sharing elements such as accessibility, symbolism and activity with the squares in the cases. 2)The shape of planes in the squares in the cases has been formed in close relations with the historic meaning and events of the area and the process of the construction of buildings surrounding the square. The squares in the cases were classified into seven plane types, and these squares have developmentally contributed to the formation of a sharing culture as a place for free participation and communication concerning social issues. 3)In the squares in the cases, the weight of road-centered access appears high, and in terms of the construction of human-friendly / environment-friendly infrastructure in the city or judging from the trend of the recent increase of pedestrian-centered plans for public space, it is judged that approaches with a high utilization rate of sidewalk or public transportation would be desirable. 4)Symbolic elements of the square become a device by which citizens can share the historic symbolism, along with artistic inspiration. In addition, by serving as an observatory from which people can take a view of the landscape of the city, it allows visual sharing of the entire city as well as the square. 5)A square is common pool resources in the community, and it is necessary to vitalize that in a direction of increasing the possibility of sharing, through the characteristics and methods of the composition of public design.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.5
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• pp.872-882
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• 2017

There are no specific guidelines on how to control the heat input for the heat generating smart base layer. This study investigated the mode of actuating heat pad attached to the base layer by performing a human wear test in a cold environment. Subjects participating in the test wore T-shirts, jumper and pants on the base layer with heating pads. Skin temperature, total time of heating and the number of switching for the heating mode were observed as the subject controlled the heating mode voluntarily. The comfortable range of skin temperature on the abdomen was larger than on the lower back. The subject felt hot and turned off the switch when the mean skin temperature of the abdomen was $48.8^{\circ}C$ and the lower back was $40.1^{\circ}C$. The total heating time and the number of actuating switching were larger for women than men. The voluntary action of heating for men with high cold sensitivity was significantly different from men with low cold sensitivity. Therefore, it is necessary (depending on gender and cold sensitivity) to set the heating mode differently for the automatic heat control of a future smart base layer.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1228-1237
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• 2005

In order to predict the long-term effects of pollutants in sediment on the water quality and the improvement of water quality according to dredging operation, models applied to decide the location and the propriety of dredging were developed. At first, the area was divided into several segments and the developed model was applied to simulate the behaviors of contaminants in an aquatic environment by using estimated parameters. And then through the sensitivity analysis between parameters, the optimum values were determined. The long-term modelling in the area A forecasted that PCBs concentration in the hot spot was decreased from $3.1\;{\mu}g/L$ to $2.4\;{\mu}g/L$ in 30 years. Contaminants in sediment as a source of water pollution did not reduce remarkably in the long run. Therefore it is difficult to expect the improvement of water qualities without the fundamental isolation of contaminants from sediment. It is considered that the selective dredging in the spot improves the water quality consequently.