• The Journal of the Acoustical Society of Korea
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• v.35 no.3
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• pp.223-233
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• 2016

Design of a vegetation type sound barrier was presented as a noise barrier on the boundary of neighborhood facilities including schools, and apartments. The suggested noise barrier is made of unit blocks that are to be formed by stacking over the wall structure containing the plant and soils in the blocks. The advantage of the vegetation noise barrier is to acquire not only sound absorptive effects of plants and soils, but also sound diffusive effect caused by the irregular surface of the barrier which could eventually mitigate the noise. First, the optimum size of the units to obtain the highest noise reduction was investigated using 1/10 scaled model experiment, and sound attenuation experiments were carried out using a 1/2 mock-up model which is 2 m high and 5 m long. Total 1,137 unit blocks were made of synthetic woods with the size of $10{\times}10{\times}9cm$. These unit blocks were installed on the both side of the 1/2 mock-up steel framed noise barrier. As a result, it was revealed that the block typed vegetation noise barrier has 7 dB higher insertion loss in comparison with the general plane noise barrier. Also, it was found that the appropriate size of unit blocks is $20{\times}20cm$ which has large effect of sound insertion loss.

• The Journal of the Acoustical Society of Korea
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• v.35 no.3
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• pp.167-174
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• 2016

Underwater communication is difficult to increase the communication capacity because the carrier frequency is lower than that of radio communications on land. This is limited to the bandwidth of the signal under the influence of the characteristics of an ocean medium. As the high transmission speed and large transmission capacity have become necessary in the limited frequency range, the studies on MIMO (Multiple Input Multiple Output) communication have been actively carried out. The performance of the MIMO communication is lower than that of the SIMO (Single Input Multiple Output) communication because cross-talk occurs due to multiusers along with inter symbol interference resulting from the channel characteristics such as delay spread and doppler spread. Although the adaptive equalizer considering multi-channels is used to mitigate the influence of the cross-talk, the algorithm is normally complicated. In this paper, time reversal mirror technique with the characteristic of a self-equalization will be applied to simplify the compensation algorithm and relieve the cross-talk in order to improve the communication performance when the signal transmitted from two channels is received over interference on one channel in the same time. In addition, the performance of the MIMO communication based on the time reversal mirror is verified using data from the SAVEX15(Shallow-water Acoustic Variability Experiment 2015) conducted at the northern area of East China Sea in May 2015.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.101-113
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• 2015

The purpose of this study is increasing ventilation network usability for urban green space planning by enhancing its practicality and detail. A ventilation network feature extraction technique using roughness length($z_0$) was proposed. Continuously surfaced DZoMs generated from $z_0$(cadastral unit) using three interpolations(IDW, Spline, and Kriging) were compared to choose the most suitable interpolation method. Ventilation network features were extracted using the most suitable interpolation technique and studied with land cover and land surface temperature by spatial overlay comparison. Results show Kriging is most suitable for DZoM and feature extraction in comparison with IDW and Spline. Kriging based features are well fit to the land surface temperature(Landsat-7 ETM+) on summer and winter nights. Noteworthy is that the produced ventilation network appears to mitigate urban heat loads at night. The practical use of proposed ventilation network features are highly expected for urban green space planning, though strict validation and enhancement should follow. (1) $z_0$ enhancement, (2) additional ventilation network interpretation and editing, (3) linking disconnected ventilation network features, and (4) associated dataset enhancement with data integrity should technically preceded to enhance the applicability of a ventilation network for green space planning. The study domain will be expanded to the Seoul metropolitan area to apply the proposed ventilation network to green space planning practice.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.243-248
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• 2014

This study has been carried out to find out current status of understanding radiation safety expertise by workers under the present training scheme and to minimize radiation risks at work as well as to refurbish training systems for mitigation of uneasiness of the people at large in near future. Questionnaire survey asking 30 items was carried out during 3 months from May to July, 2013. The number of the overall respondents were about 500. Overall scores of hath degree of the basic knowledge and of the attitude related with radiation safety could he procured through analysis of the questionnaire data. Results were as followings: The workers of the higher academic level, the larger of the accumulated training time and the worker's personal antecedents, the more accredited license holders showed the larger scores of the basic knowledge of radiation as well as the attitude related with the radiation safety. The group having higher basic knowledge also showed the higher score in attitude related with radiation safety. The overall scores obtained from the radiation workers in industrial sector were relatively lower, in general, than those of the other sectors. These results suggest that the training program might better be separately implemented. A specific training program implementation might be desirable particularly for the workers in industrial sectors so as not only to reduce radiation risks of workers but also to mitigate the uneasiness arising among the people at large.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.4
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• pp.351-356
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• 2011

Citrus unshiu (C. unshiu) Markovich were dried peel of mandarin orange, of which fresh fruit was one of the famous foods in Korea and Eastern Asia. In the oriental medicine, C. unshiu peel was known to have a diuretic effect and to strengthen spleen function. Recently, natural flavonoids of C. unshiu peel have been investigated. In this study, C. unshiu peel extract containing flavonoid-glycosides was cultured with Schizophyllum commune (S. commune) mycelia producing ${\beta}$-glu- cosidase and its biological activities were investigated. ${\beta}$-glucosidase of S. commune mycelia converted the flavonoid-glycosides (rutin and hesperidin) into aglycones (naringenin and hesperetin). Fermented C. unshiu peel extract compounds were analyzed by HPLC system. The photoprotective potential of fermented C. unshiu peel extract was tested in human dermal fibroblasts (HDFs) exposed to UVA. Fermented C. unshiu peel extract extract also showed notable in vitro anti-inflammatory effect on cellular systems generating cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) metabolites. Also, UVB-induced production of interleukin-$1{\alpha}$ in human HaCaT cells was reduced in a dose-dependent manner by treatment with fermented C. unshiu peel extract. These results suggest that fermented C. unshiu peel extract may mitigate the effects of photoaging in skin by reducing UV-induced adverse skin reaction.

• Journal of The Korean Dental Society of Anesthesiology
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• v.14 no.1
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• pp.29-39
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• 2014

Background: Dental phobia or anxiety of patients is the serious impediment to appropriate and effective dental treatment. Sedative technique helps to mitigate patients' fear and anxiety thus make them more cooperative and familiar to dental practices. With increasing attention to sedative dentistry in dentists, educational requirements and technical qualification also become stricter but actual survey on recent sedative dentistry has not been reported yet. Especially there is insufficient study reporting the survey of sedative dentistry subjected to Korean adults. In this paper, we conducted a survey study on the actual condition and practice related to sedation with a questionnaire to dentists in South Korea. Methods: The survey was done for members of The Korean Dental Society of Anesthesiology (KDSA), who had great interest in sedation and for whom survey-by-mail was convenient. 472 members of The KDSA having dental license and solid address and contact information were subjected to the survey by sending them survey questions about their sedative techniques and knowledge. In order to increase the response rate, small gifts were presented to those who accurately responded to the survey questions and text messages and phone calls were made to encourage their participation. We collected their responses over two months and examined the returned surveys. Statistical analysis was performed using IBM SPSS Statistics 21 for each question. Results: Out of 472 dentists, 181 responded (38.4% response rate). 63.0% (114 dentists; 77 male and 37 female) of respondents had experience on sedative technique and their average age was $39.8{\pm}7.6$ year. 74 of them were private practitioners, 17 of them were professors (14.9%), 11 of them were dentists-in-service (9.6%), 11 of them were residents (specialist training) (9.6%) and 1 of them was military doctors (0.9%). There were 89 dentists (78.1%) who were specialists or receiving trainings to be specialist, most of whom were pediatric dentists (55, 48.2%) and oral surgeon (31, 27.2%). The most popular route for drug medications was orderly oral, inhalational, intravenous medication. Combination of oral and inhalational medications or single use of intravenous medication was the most common. The most preferred sedative drug was pocral in oral sedation and midazolam in intravenous sedation. 48.2% of practitioners responded that they experienced side effects and emergency situations. Airway obstruction was the most frequent. Conclusions: Results from the survey show that the protocol and system for sedative dentistry have been improved compared to the past. Nevertheless, quality of emergency protocol, monitoring devices and preparation of sedative drugs was still insufficient to achieve safe sedative procedure. This study acquires novelty since actual survey on recent sedative dentistry for adult patients has not been reported yet.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.617-625
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• 2012

This study examines the current status and policy development of Carbon Dioxide Capture and Storage(CCS), which is a technology to mitigate climate change, in Korea and foreign countries. It also analyzes IEA CCS regulatory framework as a guideline and provides limitations and implications for marine geological storage in the Republic of Korea. Although CCS master plan is established at national level, related laws are not amended and detailed polices are not yet provided. Established 'Intergovernmental CCS committee' lacks its cooperative mechanism and flexibility. Only limited and segmented economic analyses are performed and funding for large scale of CCS project is not secured. In addition, information sharing is limited and public awareness activities are insufficient. Therefore, this paper provides some policy suggestions on establishing a legal framework based on the 'Marine Environmental Management Act', strengthening the role of intergovernmental CCS committee, conducting CCS economic analysis based on various scenarios, providing economic incentives and public participation strategies, and establishing a specialized agency for information sharing.

• Journal of the Korean Electrochemical Society
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• v.13 no.4
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• pp.256-263
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• 2010

A Crofer 22 APU mesh coated with a conductive ceramic material was developed as an alternative cathode current collector to Ag-based materials for solid oxide fuel cells. $(La_{0.80}Sr_{0.20})_{0.98}MnO_3$ (LSM) layer was deposited onto the Crofer mesh using a spray-coating technique, in an attempt to mitigate the degradation of electrical properties due to surface oxidation at high temperatures. The oxidation experiments at $800^{\circ}C$ in air indicated that the areaspecific resistance (ASR) of the LSM-coated Crofer mesh was strongly dependent on the wire diameter and the contact morphology between mesh and cell. In addition, the post-heat-treatment in $H_2/N_2$ resulted in a reduced thickness of Cr-containing oxide scales at the interface between Crofer mesh and LSM layer, leading to a decreased ASR.

• Journal of Korean Academy of Nursing
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• v.28 no.2
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• pp.498-509
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• 1998

The phrases such as elders' powerless soliloquy or stammering and their positions unadjusted to the real world are, so far, one of negative views on elder's reminiscences. In other words, it means that elders can get psychological consolation from the getting themselves absorbed in their past. The starting point of this study is, however, that elders' reminiscence are their own mode of the existence. This dissertation is studied through Van Manen's phenomenological research method. The aim of this study is to examine the nature of Korean elders' reminiscences by both observing and describing the reminiscing content in everyday life of elders. The research participants consist of the ten elders who are community elders, hospitalized elders and nursing home residents. The period of the research is about a year from Jan., 1996 to Feb., 1997. The results of this study are as follows : The natures of elders' reminiscences are the regrecting on their life, mitigating the regrects, the confirmation of the powers and the confirmation of their life's mark. The regrecting on their life is the starting point of elders's reminiscences. Elders have tried to examine their life through reflection on their life that they did not live good life as son and daughter for parents and as parents for children and that they have foolishly lived, on dream that they did not come true, on their learning that they did not unsatisfied. But elders mitigate the regrects. They have felt their limitations of power in the conflict of human relation, the economic matter and the difficult predicament, and have finally accepted their life as it is by conquesting from their tenacity. It is dynamically found that both the regrecting on their life and mitigating of the regrection. And they pursuit the powers. It means the pursuit of the vital powers, the vigorous powers and the competency. Elders have pursued their vitality, vigor and competency through their reminiscences and have wanted to be recognised by others as a powerful being. These have dynamic and compounded aspects. The confirmation of their life's mark refer to through their own situation of health, condition, children, neighbourhood and doing their duty as a human. Elders have confirmed the present value of their being through the reflecting the present, past self, other men around themselves, children, neighborhood and the doing their human duty as a good men. Therefore the results of this study can offer new view on the elders' reminiscences that we have to understand them as a process as what they are, escaping from the simple logic that elders' reminiscence have a positive or a negative effects. Also, this study which have examined the natures of Korean elders' reminiscences can cast a new light on elders' nursing proper for Korean culture.

• Clean Technology
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• v.7 no.1
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• pp.13-25
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• 2001

With fast advancement of fine machineries and semiconductor industries in recent decades, the ultra-cleaning of organic chemicals, submicron particles from contaminated unit equipments and products such as silicon wafers becomes one of the most important steps for further advancement of such industries. To date, two kinds of ultra cleaning techniques are used; one is the wet-cleaning and the other is the dry cleaning. In case of wet cleaning, removal of organic contaminants and submicron particles is made by DIW with additives such as $H_2O_2$, $H_2SO_4$, HCl, $NH_4OH$ and HF, etc. While the wet cleaning method is most widely adopted for various occasions, it is inevitable to discharge significant amount of toxic waste waters in environment. Dry cleaning is an alternative method to mitigate environmental pollution of the wet cleaning with maintaining comparable degree of cleaning to the wet cleaning. Although there are various concept of dry cleaning have been devised, the dry cleaning with environmentally-benign solvent such as carbon dioxide proven to show high degree of cleaning from the contaminated porous surface as well as from the bare surface. Thus, special global attention has been placing on this technique since it has important advantages of simple process schemes and no environmentally concern, etc. Thus, this article critically reviews the state-of-the-art of the supercritical fluid drying with emphasis on the thermo-physical characteristics of the supercritical solvent, environmental gains compared to other dry cleaning methods, and the generic aspects of the basic design and processing engineering.