• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1475-1486
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• 2008

Bentonite-based grouting has been popularly used to seal a borehole installed for a closed-loop vertical ground heat exchanger in a geothermal heat pump system (GHP) because its high swelling potential. However, if the bentonite-based grouting is conducted in coastal areas, the salinity of groundwater changes in the mineral fabric of bentontie. In order words, an increase of cation concentration in groundwater leads to a reduction in the diffuse double-layer thickness in the bentonite mineral structure, and thus the volume of bentointe-based grouts will decrease proportional to the salinity of groundwater. In this paper, the effect of salinity (i.e., NaCl 0.5M, 0.25M, and 0.1M) on the change of swelling potential for bentonite-based grouts has been quantitatively evaluated for seven bentonite grouts from different product sources. In addition, in case of using addictives such as a silica sand to increase the thermal conductivity of bentonite-based grouts, the possibility of particle segregation has been studied considering the viscosity of grouts and salinity of groundwater.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1181-1185
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• 2005

A combining of MIMO signal processing with OFDM is regarded as a promising solution of enhancing the performance of next generation wireless system. Therefore, in this paper, an OFDM-based wireless system employing layered space-time architecture is considered for a high-rate transmission. In the MIMO-OFDM system, we evaluate the PAR performance using the SLM approaches. The investigated SLM scheme for MIMO-OFDM signals selects the transmitted sequence with lowest average PAR over all transmitting antennas and retrieves the side information very accurately at the expense of a slight degradation of the PAR performance. The low probability of false side information can improve the overall detection performance of the MIMO-OFDM system with erroneous side information compared to the ordinary SLM approache, respectively. Also, we provide closed form of the average BER performance in MIMO-OFDM system using analytic approach.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.45-56
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• 2014

Frozen ground in cold region consists of an upper active layer and lower permafrost which is permanently frozen land. During the summer season, the air temperature is high enough to make the frozen ground melt, which causes the reduction of soil strength and thaw settlement. These phenomena result in structural instability, so it is necessary to apply frozen ground stability techniques. Thermosyphon is a closed natural two-phase convection device to maintain the ground temperature below $0^{\circ}C$ by extracting heat from the ground and discharges it into the atmosphere. Experimental and numerical investigation has been performed to estimate the effect of the refrigerant filling ratio in thermosyphon using R-134a refrigerant and the thermal conductance of the thermosyphon.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.555-560
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• 2005

The nose is shaped as a pyramid and is the most prominent portion of the face. Nasal bone fractures are thus more frequent than those of the maxilla and zygoma. Whether the nasal bone fractures are corrected or not due to unnecessity of surgical treatment, the incidence of posttraumatic deformity occurs frequently. In Asian patients, even the corrected noses look low-lying and flat. To resolve these problems, we corrected the posttraumatic deformity of the nose with a combined procedure of nasal ostectomy and augmentation rhinoplasty. From 2000 to 2004, this procedure was performed in fifteen patients with posttraumatic nasal deformity. There were four female and eleven male patients with an average age of 32 years(range 19 to 52 years). All patients had previous trauma history. Of these, closed reduction was performed on 13 patients and no treatment was 2 patients. The deformed noses were corrected through lower columellar incision, by ostectomy or osteomy, and augmentation with silicone implant. We gained satisfactory results of correcting the deformed noses, except one case with implant deviation. Our method for the correction of traumatic nasal deformity proves to be simple and safe. The camouflage effect with silicone implant overcomes an unsatisfactory correction and brings a excellent cosmetic results.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.66-73
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• 1998

This paper deals with the combustion characteristics of flue gas in infared mobile heaters. The experimental work has been performed to obtain the concentration levels and combustion characteristics of flue gas with varying chamber size and room temperature. The experimental results showed that oxygen depletion sensor device was operated at the oxygen concentration level of $18.3\%$ for all the chamber size. The combustion characteristics of oxygen and carbon dioxide show a linearity After 10 minutes the combustion property of carbon monoxide occurs at random without a level of oxygen and carbon dioxide in closed space of the heater. In these results, it is very important to prevent incomplete combustion through a sufficient ventilation, and accident prevention with a reduction of the oxygen and diffusion of toxic carbon monoxide.

• Analytical Science and Technology
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• v.32 no.5
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• pp.196-209
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• 2019

As a traditional method to apply fingerprint powder, brush method ("dusting") can create a risk to the health of crime scene investigators due to the inhalation toxicity of harmful and fine powders. Therefore, as a new method of applying powders, we tried to evaluate the potential of a chamber method for the development of latent fingerprint using fans in a closed chamber with a fixed capacity that can prevent the powders from being blown outside and exposed to the users, by comparing with the development results of the conventional brush method. Fingerprints on glass and plastic (PET) were extracted with black powder and green fluorescent powder, and the sharpness and minutiae of the developed fingerprints were compared for each method. The results of the black powder showed similar results, but the effect of the chamber method was slightly decreased when the green fluorescent powder was used. In order to improve the development with the green fluorescent powder, the mixture (50 : 50) of the fluorescent powder with the silica gel was tested and the results were similar to those of the brush method. It is expected that the chamber method has a high potential as a new powder application method considering the health of the crime scene investigator after fine tuning of development conditions with additional studies.

• Journal of Korea Port Economic Association
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• v.18 no.2
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• pp.65-90
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• 2002

Despite the importance and necessity, the 3PL has not been activated to date. Among many views, customers claim that logistics service provider(LSP) are not prepared or capable of offering satisfactory 3PL services, while LSP emphasize the lack of mutual trust, closed corporate culture of the customer and excessive demand for reducing the costs. With this keeping in mind, it surveyed difference of perception between users and providers of 3PL services in terms of the actual status of using 3PL services, the degree of satisfaction and key factors for selecting 3PL provider through the questionnaire. As shown in this study, 43.3％ of the respondents outsourced logistics services. However, Most company outsourced only inland transportation (49.5％) which is a simple and limited scope of 3PL services, but it also indicated that the percentage of users have ranged was less then 10% in outsourcing their whole logistics sector to 3PL provider and employing other logistics functions. Among respondents, a majority of the service provider stated that they offered satisfactory cost-saving to the customers, while users felt that the degree of satisfaction for using 3PL services was evaluated as at an average level and they more highly regarded the strong partnership of their 3PL provider rather than the saving of cost and improvement of customer's services. Moreover, in contrast to the 3PL providers which regard the most important factor for selecting 3PL service provider is the logistics cost quoted, users of 3PL services felt that the quality of services was more significant than the reduction of cost, and this tendency for selecting 3PL providers was shown in more advanced countries. While users of 3PL services indicated that the main reason for not using 3PL services was to avoid disclosing information of their business and it costs much for employing 3PL providers than doing themselves, 3PL providers thought it was due to reluctancy of opening information and resistance from the logistics division engaged in logistics activities concerned. Accordingly, providers and users of 3PL services should trust each other and prepare plan to activate 3PL services under the collaborative relationships as soon as possible.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.648-657
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• 2015

Soil organic matter (SOM) plays an important role in the continuous production and environmental conservation in arable soils. In particular, the decomposition of organic matter in soil might promote soil organic matter and fertility due to the mineralization of N. In this study, to evaluate the effect of organic matter amendment on the C mineralization and N dynamic, $CO_2-C$ flux, extractable N and $N_2O$ emission were determined using closed chamber for 4 weeks at 10, 15, $20^{\circ}C$ of incubation temperature after the mixture of $2Mgha^{-1}$ rice straw compost and rye in sandy loam and clay loam. Regardless of soil texture, decomposition rates of rice straw compost and rye at $10{\sim}20^{\circ}C$ of incubation temperature ranged from 0.9 to 3.8% and 8.8 to 20.3%, respectively. Rye application in soil increased $NH_4-N$ and $NO_3-N$ content as well as the $N_2O$ emission compared to the rice straw compost. After incubation for 4 weeks, total C content in two soils was higher in rice straw compost than in rye application. In conclusion, application of rice straw compost and rye to soil was able to improve the soil organic matter and fertility. However, organic matter including the recalcitrant compounds like rice straw compost would be effective on the management of soil organic matter and the reduction of greenhouse gases in soil.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.365-372
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• 2021

Objectives: Mandibular fractures vary significantly with respect to epidemiological and demographic parameters among populations. To date, no study has evaluated these aspects of mandibular fractures in Nuh, Mewat, Haryana, India. To retrospectively analyze the incidence, age and sex distributions, etiology, anatomic distribution, occlusal status, treatment modality provided, and their correlation in patients who suffered isolated mandibular fractures. Materials and Methods: The records of maxillofacial injury patients who reported to the Department of Dentistry, SHKM Government Medical College from January 2013 to December 2019, were retrieved from our database, and necessary information was collected. The data collected were analyzed statistically using IBM SPSS ver. 21. Results: Totals of 146 patients and 211 fractures were analyzed. There were 127 males and 19 females with an age range of 3-70 years (mean age, 26 years). Road traffic accident (RTA) was the most common cause of fracture (64.4%), followed by fall (19.9%), assault (15.1%), and sports injury (0.7%). Of all patients, 42.5% had bilateral fractures, 31.5% had left side fracture, 21.2% had right side fracture, 3.4% sustained midline symphyseal fracture, and 1.4% had symphyseal fracture along one side of the mandible. Site distribution was as follows: parasymphysis (34.6%), angle (23.7%), condyle (20.4%), body (12.8%), symphysis (4.3%), ramus 2.4%, and dentoalveolar 1.9%. The most common facture combination was angle with parasymphysis (17.8%). Occlusion was disrupted in 69.2% patients. Closed reduction was the predominant treatment modality. Conclusion: The data obtained from retrospective analyses of maxillofacial trauma increase the understanding of variables and their outcomes among populations. The results of the present study are comparable to those of the literature in some aspects and different in others.

• Archives of Craniofacial Surgery
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• v.19 no.4
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• pp.270-274
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• 2018

Background: Nasal bone fractures occur frequently because the nasal bone is located at the forefront of the face. The goal of this study was to examine the cause, change in severity, change in incidence, and demographics of nasal bone fracture according to today's lifestyle. Methods: A total of 2,092 patients diagnosed as having nasal bone fractures at our department between 2002 and 2017 were included in this study. We retrospectively examined patients' medical records to extract information regarding age, sex, cause of injury, combined facial bone fractures, and related injuries such as skull base fracture, spinal cord injury, brain hemorrhage, and other bone fractures. Fracture severity was classified by nasal bone fracture type. Results: No statistically significant difference was found in annual number of patients treated for nasal bone fracture. The proportion of patients who underwent closed reduction was significantly decreased over time for those with nasal bone fractures caused by traffic accidents. However, it was not significantly changed for those with nasal bone fractures due to other causes. The number of patients with combined facial bone fractures increased over time. Incidences of severe nasal bone fracture also increased over time. Conclusion: The study suggested that there is a decrease in the frequency and increase in the severity of nasal bone fracture due to traffic accident. Many protective devices prevent nasal bone fractures caused by a small amount of external force; however, these devices are not effective against higher amounts of external force. This study highlights the importance of preoperative thorough evaluation to manage patients with nasal bone fractures due to traffic accident.