• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.18-22
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• 2010

In this paper, we propose and analyze the two way ranging (TWR) positioning technique using ultra wideband (UWB) for indoor environment. We employed IEEE 802.15.3a channel as a simulation environment and used to time of arrival (TOA) algorithm. UWB technology in a low transmission power the less the effect of interfering with the existing system, the frequency can be shared so that it can improve the spectral efficiency. And, positioning technique based on UWB with a very narrow pulse width has high accuracy in indoor environment. From the simulation results, it is analyzed the probability of error and positioning performance for channel effects and confirmed usefulness of the proposed scheme.

• The Journal of the Acoustical Society of Korea
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• v.15 no.3E
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• pp.86-94
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• 1996

The aims of this study were to describe the way in which sound durations are perceived, and to attempt to explain the hidden mechanisms of the duration perception in music performances. Three experiments were carried out to determine the difference limen for the perception of sound duration and to find the effects of frequency and intensity on duration discrimination. For short duration tones ranging from 25 to 100 msec, a linear improvement in discrimination judgements was found with increasing duration of signal. The JND was constant for durations between 100 msec and 2 sec. However, for extended stimulus durations (more than 2 sec) the JND was again linearly improved. Subjects were also presented with a pair of stimuli, composed of high and low frequency pure tones, and asked to discriminate differences in duration of the two tones and ignore differences in the frequency of the tones. It was found that subjects perceived the higher frequency to be longer in duration. When an experiment was carried out to investigate the effect of intensity on duration discrimination it was found that a 20 phon difference makes subjects perceive the louder stimulus as longer than the quieter stimulus. Finally, in a performance study, an analysis of musical performances revealed the effect of frequency. It was found that the musicians played the higher notes shorter than the lower notes. This agrees with what was previously found in the work on the perception of tones.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.69-77
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• 2021

The objective of this research is to explore the inconclusive theoretical and empirical association between institutional ownership and firm performance in the context of emerging Pakistani economy. The data set consists of all the non-financial firms listed on the Pakistan Stock Exchange (PSX). Annual data set covers the period ranging from 2010 to 2015. However, the econometric analysis does not include those firms with incomplete data. Thus the final data set comprised of an unbalanced panel of sample of 276 firms with 1231 firms years observations. Data related to the institutional ownership and other variables taken for the study were extracted through the annual financial reports of the firms. The research used Tobin's Q as a proxy of market measure of firm performance and tested the endogenous relation with institutional ownership through OLS and 2SLS approach. The study also applied Durbin-Wu-Hausman test to determine the endogeneity before analyzing the 2SLS model. The Durbin-Wu-Hausman Test (DWH) conform the endogenous link between institutional ownership and performance and vice versa. The results derived from 2SLS also confirm a highly significant relationship and two way direct proportional relationships between the institutional investment and corporate performance in the studied companies.

• Journal of Fashion Business
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• v.23 no.4
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• pp.86-99
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• 2019

This research is a study on up cycling design to protect nature in order to postpone global warming to the maximum extent possible as it has been a serious global issue to the fashion industry and even to individual consumers. This research focuses on the ways to use wedding dress, one of the clothes made of synthetic fiber, which is a major cause of global warming. Among clothing from the 19th century, two styles of clothes, Bustle style and Art Nouveau style were analyzed ranging from their underwear styles to outwear styles through collections in books and museums. Two styles of dress using drawers, chemise, and corset as basic underwears were manufactured. All the fabric and subsidiary materials except for parts of underwears were made with discarded wedding dresses. It was developed for rental clothing which women could try on Western costume, from underwears to outwears. First, for bustle dress, woman put on basic underwears, then bustle, and bustle-type petticoat. Dress is a two-piece type, and it was made to put on detachable train on the back of skirt. Second, based on the Art Nouveau style clothes, our-glass style dress consists of petticoat, one-piece over drawers, chemise, and corset. After putting on drawers, both chemise, and corset were the same as Bustle Style. This research is a practical way of realizing sustainable design. The aim of the current work is to provide educational effect on the development of rental clothes which upcycle wedding dress and let women experience other cultures.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.123-133
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• 2017

The development of a new manufacturing process, a two-step temperature treatment, to modulate the physicochemical properties of nanoparticles including the size is critical. This is because its physicochemical properties can be key factors affecting the cellular uptake and the bioavailability of bioactive compounds encapsulated in nanoparticles. The aims of this study were to produce (beta-lactoglobulin) ${\beta}-lg$ nanoparticles and to understand how two-step temperature treatment could affect the formation and physicochemical properties of ${\beta}-lg$ nanoparticles. The morphological and physicochemical properties of ${\beta}-lg$ nanoparticles were determined using atomic force microscopy and a particle size analyzer, respectively. Circular dichroism spectroscopy was used to investigate the secondary structure of ${\beta}-lg$. The surface hydrophobicity and free thiol groups of ${\beta}-lg$ were increased with a decrease in sub-ambient temperature and an increase in mild heat temperature. As sub-ambient temperature was decreased, a decrease in ${\alpha}-helical$ content and an increase in ${\beta}-sheet$ content were observed. The two-step temperature treatment firstly involved a sub-ambient temperature treatment from 5 to $20^{\circ}C$ for 30 min, followed secondly by a mild heat temperature treatment from 55 to $75^{\circ}C$ for 10 min. This resulted in the production of spherically-shaped particles with a size ranging from 61 to 214 nm. Two-way ANOVA exhibited the finding that both sub-ambient and mild heat temperature significantly (p<0.0001) affected the size of nanoparticles. Zeta-potential values of ${\beta}-lg$ nanoparticles were reduced with increasing mild heat temperature. In conclusion, two-step temperature treatment was shown to play an important role in the manufacturing process - both due to its inducement of the conformational changes of ${\beta}-lg$ during nanoparticle formation, and due to its modulation of the physicochemical properties of ${\beta}-lg$ nanoparticles.

• The Korean Journal of Archival Studies
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• no.5
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• pp.39-85
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• 2002

This paper is aimed at proposing the policies for managing archives in the process of promoting Electronic Government System. Although there have been many studies of electronic government project and plans for its establishment, this research examines the electronic government system and its problems on the basis of archival science. What I acquired in this paper is as follows. The development of information technology needs great changes ranging from the nation to the individuals. It becomes common that the use of computerized program for business purposes, computerization of information materials and the effective way of search use of electronic documents. Therefore, more and more countries all over the world have been seeking to promote 'Electronic Government', which applies the fruits of the development in information technology to administration process. Recently, Korea has been rapidly entered into the 'Electronic Government' system being against the traditional way of administration. In electronic government system, the 'Life Cycle' of public records will be computerized. Therefore, it is important to change and develop along with the government's policies for 'electronic government project' in the archival management system. This means that the archival management system which have put emphasis on the textual records should be converted to electronic records system. In other words, the records management in electronic government system requires not the transfer and preservation of the records but the consistent management system including the whole process of creating, appraising, arranging, preserving and using the records. So, the systematic management of electronic records plays an important role in realization of electronic government, but it is a subject to be realized by electronic government at the same time. However, the government have overlooked the importance of archival management for long time, especially the importance of electronic records management system. First of all, this research attempts to infer limits and problems through the theoretical considerations of the existing studies for electronic government and to clear up the relations between electronic government and archival management. Based on this, I'll seek to progress the study through reviewing the present condition of archival management in the process of promoting electronic government and suggesting the policies for enhancing the successful electronic government and the construction of scientific archival management system. Since early 1990, many countries in the world have been making every effort to concrete 'Electronic Government'. Using the examples in other nations, it is not difficult to recognize that the embodiment of electronic government is closely connected with the archival management policies. Korea have completed legal and institutional equipments including the new establishment of "Electronic Government Law" to realize electronic government. Also, Korea has been promoting electronic government with the Ministry of Government Administration and Home Affairs and Government Computer Center as a leaders. Though managing records, especially the management of electronic records is essential in electronic government system, we haven't yet discussed this section in Korea. This is disapproved by the fact the Government Archives and Records Service has played little role in promoting electronic government project. There are two problems relating this environment. First, present system can't meet the consistent 'Life Cycle' ranging from the creation to the preservation of electronic records. Second, the 'Life Cycle' of electronic records is divided into two parts and managed separately by GCC and GARS. The life of records is not end with the process raged from creation to distribution. On the other hand, the records are approved their value only whole procedures. Therefore, GARS should play a deading role in designing and establishing the archival management system. The answer to these problems, is as follows. First, we have to complete the electronic records management system through introducing ERMS not EDMS. This means that we should not change and develop towards ERMS simply with supplementing the current electronic records management system. I confirm that it is important and proper to establish ERMS system from the very beginning of the process of promoting electronic government. Second, I suggest the developmental integration of GARS and GCC. At present, the divided operations of GCC and GARS, the former is in charge of the management center for electronic business and the latter is the hub institution of managing nation's records and archives result in many obstacles in establishing electronic government system and accomplishing the duties of systematic archival management. Therefore, I conclude that the expansive movement towards 'National Archives' through the integration among the related agencies will make a great contribution to the realization of electronic government and the establishment of archival management system. In addition to this, it will be of much help to constitute and operate the 'Task Force' regarding the management of electronic records with the two institution as the central figures.

• Particle and aerosol research
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• v.8 no.1
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• pp.17-28
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• 2012

Air pollution levels of gases and aerosol particles inside the Jeongneung and Hongjimun tunnels of the Naebu express way in Seoul were investigated through on-road measurement using a mobile emission laboratory (MEL) on February 8, 2011. The concentrations of $NO_x$, $CO_2$, number concentration of particles ranging 21-560 nm, and surface area of particles deposited on a human lung almost linearly increased with increasing distance from the tunnel entrance, and decreased rapidly before the tunnel exit. This trend was observed regardless of tunnel length and driving directions, which thought to be caused by semi-transverse ventilation facilities of the tunnels. The concentration increments per 1-m distance for $NO_x$, $CO_2$, deposited particle surface area, and number of particles ranging 21-560 nm were 0.61~0.80 ppb, 0.16~0.21 ppm, $0.20{\sim}0.29{\mu}m^2/cm^3$, and 117~192 particles/$cm^3$, respectively. Average pollution levels inside the two tunnels for $CO_2$, deposited particle surface area, and number of particles >5.6 nm ranged 681~748 ppm, $246{\sim}381{\mu}m^2/cm^3$, and $2.4{\sim}6.7{\times}10^5$ particles/$cm^3$, respectively. In case of $NO_x$, the maximum concentration exceeded 1 ppm. These pollution levels inside the tunnels are much higher than those at urban background sites. This result can be utilized as basic data to evaluate the effectiveness of present ventilation system for reducing the pollution level caused by vehicles inside the tunnels.

• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.182-187
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• 2017

PURPOSE. Vinyl polyether silicone (VPES) has a different composition from other elastomeric impression materials as it combines vinyl polysiloxane (VPS) and polyether (PE). Therefore, it is important to study its properties and behavior under different test conditions. This study investigated the dimensional stability of 5 VPES consistencies when stored for up to 2 weeks, with and without using a standard disinfection procedure. MATERIALS AND METHODS. 40 discs of each VPES consistency (total 200) were made using a stainless steel die and ring as described by ANSI /ADA specification No. 19. 20 discs of each material were immersed in a 2.5% buffered glutaraldehyde solution for 30 minutes. Dimensional stability measurements were calculated immediately after fabrication and repeated on the same discs after 7 and 14 days of storage. The data was analyzed using two-way ANOVA with a significance level set at ${\alpha}=0.05$. RESULTS. The discs mean contraction was below 0.5% at all test times ranging from $0.200{\pm}0.014$ to $0.325{\pm}0.007$. Repeated measures ANOVA showed a statistically significant difference after 2-week storage between the disinfected and non-disinfected groups (P < .001). Although there was no statistically significant difference between the materials at the time of fabrication, the contraction of the materials increased with storage for 1 and 2 weeks. CONCLUSION. The dimensional changes of VPES impression discs after disinfection and prolonged storage complied with ANSI/ADA standard. The tested VPES impression materials were dimensionally stable for clinical use after disinfection for 30 minutes in glutaraldehyde and storage for up to 2 weeks.

• Journal of Korean Society on Water Environment
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• v.34 no.1
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• pp.121-131
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• 2018

Domestic sewage treatment plants (STPs) consume about 0.5 % of total electric energy produced annually, which is equivalent to 207.7 billion Korean won per year. To minimize the energy consumption and as a way of mitigating the depletion of energy sources, the sewage treatment strategy should be improved to the level of "energy positive". The core processes for the energy positive sewage treatment include A-stage for energy recovery and B-stage for energy-efficient nitrogen removal. The integrated process is known as the A/B-process. In A-stage, chemically enhanced primary treatment (CEPT) or high rate activated sludge (HRAS) processes can be utilized by modifying the primary settling in the first stage of sewage treatment. CEPT utilizes chemical coagulation and flocculation, while HRAS applies returned activated sludge for the efficient recovery of organic contents. The two processes showed organic recovery efficiencies ranging from 60 to 70 %. At a given recovery efficiency of 80 %, 17.3 % of energy potential ($1,398kJ/m^3$) is recovered through the anaerobic digestion and combustion of methane. Besides, anaerobic membrane bioreactor (AnMBR) can recover 85% of organic contents and generate $1,580kJ/m^3$ from the sewage. The recovered energy is equal to the amount of energy consumption by sewage treatment equipped with anaerobic ammonium oxidation (ANAMMOX)-based B-stage, $810{\sim}1,620kJ/m^3$. Therefore, it is possible to upgrade STPs as efficient as energy neutral. However, additional novel technologies, such as, fuel cell and co-digestion, should be applied to achieve "energy positive" sewage treatment.

• Archives of Plastic Surgery
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• v.39 no.2
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• pp.162-165
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• 2012

The synchondrosis between the sixth and seventh costal cartilage is usually used for the base frame in autogenous ear reconstruction. If the synchondrosis is loose, a variety of modifications can be devised. This report introduces new methods for these problems. In cases of incomplete synchondrosis, only the surface of the base block margin was smoothly tapered without carving for the removal of the conchal deepening. The secure fixation of the two segments (helix and antihelix) to the base block using fine wire sutures gave stability to the unstable basal frame. After confirming that all the segments were assembled in one stable piece, the remaining conchal deepening of the basal framework was removed, and the outer lower portion of the basal cartilage was trimmed along its whole length. A total of 10 consecutive patients with microtia, ranging from 8 to 13 years old, were treated from 2008 to 2009. The follow-up period was 6 months to 2 years. Despite incomplete synchondrosis, the stable frameworks were constructed using the authors' method and aesthetically acceptable results were achieved. The proposed method can provide an easy way to make a stable cartilage framework regardless of the variable conditions of synchondrosis.