• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.76-81
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• 2021

A plastic noise barrier is a structure installed to minimize noise, and it is composed of the main plate, sound-absorbing plate, and sound-absorbing material. Plastic noise barrier structures have several advantages compared to other products, such as light weight, anticorrosion, durability, easy assembly, rapid construction, and low costs. In this study, the main and sound-absorbing plates were manufactured through extrusion molding, and the sound-absorbing plate was finished with a press to improve the conventional injection molding. Extrusion molding dies and punch dies were designed, and a profile extrusion-molding system was developed. Thus, inexpensive and efficient sound-absorbing and main plates can be produced, and the noise barrier structure can be assembled rapidly. Additionally, a noise barrier structure with extended service life and excellent quality can be constructed by creating uniform free space to accommodate increased temperatures after assembly and installation.

• Korean Journal of Metals and Materials
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• v.47 no.2
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• pp.79-90
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• 2009

A study has been made about the effects of powder content, reaction temperature, reaction time, and stirring speed on the preparation of the stainless steel(STS) 304L powders plating with copper by an electroless plating method. The behavior of corrosion resistance of the sintered STS-Cu composite powders was also investigated by the salt spraying test The electroless plating technique was an effective method to manufactur the copper-uniform plating composite powders, the corrosion resistance of this sintered specimen was improved bysuppressing Cr precipitates on grain boundaries in the sintered compacts of composite powders.

• Korean Journal of Plant Taxonomy
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• v.53 no.3
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• pp.213-221
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• 2023

A newly recorded species, Boehmeria nakashimae Yahara, is confirmed for the first time to be distributed on forest edges on Jejudo Island, Korea. This species is known to be endemic to northern Kyushu, Japan. It is characterized by ovate to broadly ovate, elliptic-ovate, or sub-orbicular middle leaf shapes, serrulate-dentate and uniform margins, 17-29 teeth on one side, a short caudate or narrowly acute apex, dense glomerules at fruiting, and densely strigillose on the stems, both surfaces of the leaves, the perianth of staminate flowers, and achenes. Therefore, it is given the new name 'Je-ju-top-mo-si-pul' in Korean based on its serrulate-dentate leaf margin and geographical distribution. A description, photographs, illustrations, and keys of related taxa in Korea are provided.

• International Journal of Computer Science & Network Security
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• v.24 no.3
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• pp.71-82
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• 2024

This paper proposes a new communication system for e-learning applications to mitigate the negative impacts of COVID-19 where the online massive demands impact the current commu-nications systems infrastructures and capabilities. The proposed system utilizes high-altitude platforms (HAPs) for fast and efficient connectivity provision to bridge the communication in-frastructure gap in the current pandemic. The system model is investigated, and its performance is analyzed using adaptive antenna arrays to achieve high quality and high transmission data rates at the student premises. In addition, the single beam and multibeam HAP radio coverage scenarios are examined using tapered uniform concentric circular arrays to achieve feasible communication link requirements.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.73-82
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• 2009

Location-based concierge services (LBCS) are considered to be one of the main service functions provided in a city in ubiquitous technology spaces. A "Ubiquitous City" is defined as a city in which both public and private services can be delivered and received anywhere and anytime. One of the key elements that make location-based concierge services successful is the interoperability of location data. Currently, several existing technologies could provide LBCS including car navigation services and ubiquitous computing. However, lack of standardized structure for location data makes it impossible for heterogeneous technologies to be able to deliver uniform LBCS. The purpose of this paper is to develop standardized locational data structure so that heterogeneous technologies could provide efficient LBCS to all users of the various transportation modes.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.1
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• pp.35-40
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• 2005

Recently, the location based service for moving customers is becoming one of the most important service in mobile communication area and for moving object applications, there are lots of update operations and such update loads are concentrated on some particular area unevenly. The primary processing of LBS application is spatio-temporal range queries and to improve the throughput of spatio-temporal range queries, the time of disk I/O in query processing should be reduced. In this paper, we adopt non-uniform two-level grid index structure, which are designed to minimize update operations. We propose query scheduling technique using spatial relationship and time relationship and a combined spatio-temporal query processing method using time zone concepts to improve the throughput of query processing. Some experimental results are shown for range queries with different query range to show the performance tradeoffs of the proposed methods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.78-84
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• 2006

As electric power systems have been moving from a vertically integrated structure to a deregulated environment, calculating reactive power service charges is a new challenging theme for market operators. This paper examines various methods for reactive power management adopted in some deregulated foreign and domestic markets and then proposes a new method to calculate reactive power service charges using a reactive power market. The reactive power market is operated based on bids from the generating sources and is settled on uniform prices by running reactive OPF programs after the day-ahead electricity market. The proposed method takes into account recovering not only the costs of installed capacity but also the lost opportunity costs incurred by reducing active power output to increase reactive power production. A numerical sample study is carried out to illustrate the processes and appropriateness of the proposed method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.7-14
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• 2021

By changing the bulky monolithic services architecture to a microservices-based architecture, industries are managing the rising complexity of Autonomous Vehicles. However, the underlying communication mechanisms for the utilization and distribution of these microservices are incapable of fulfilling the requirements of the futuristic AV, because of the stringent latency requirements along with intermittent and short-lived connectivity issues. This paper proposes to tackle these challenges by employing the revolutionary information-centric networking (ICN) paradigm as an underlying communication architecture. This paper argues that a microservice approach to building autonomous vehicle systems should utilize ICN to achieve effective service utilization, efficient distribution, and uniform service discovery. This research claims that the vision of an information-centric microservices will help to focus on research that can fill in current communication gaps preventing more effective, and lightweight autonomous vehicle services and communication protocols.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.119-128
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• 1997

The purpose of this study is to examine the military look, which is one of the most popular fashion trends in the 1996 women's fashion. Military look is that imitates or reinterprets the Army uniform which is functionally useful. After World War 1 , military look appeared in the women's fashion which is functionable tailor suits style, ankle-length skirt, pants or boiler suits for work wear, overcoat against the cold, and there was an attempt to introduce a National Standard Dress. In the middle of World War II, there was a similiar circumstance in women's military fashion. There were functionable tailor suits, knee-length skirt, pants or siren suits for work wear. And the Utility Dress was nationally recommended. In addition, the regulations were introduced to control the materials and styles used for some clothes. In the 70s, as the resistance movement as counterculture began to wear Army look which was army-uniform or army caps with 'US ARMY' logo and badges, and became very popular among the youth. In the 90s, military look has got one of the fashionable fashion themes with revival of Neo- Hippie look. Not only street fashion but also high fashion designer selected the trend for '96A/W The characteristics of the military look are khaki colors or camouflage prints, epaulets, big outpockets with flap, golden buttons and army belt. As I examined, during the World War I and ll, women wore the military look because of shortage of goods and work or service, and it was recommended by government. Though the military look in 70s, began by the resistance movement, at least it became a popular fashion. Military look in 90s, does not have inner symbolic meaning or ideology but it only represents fashion trend and revival fashion.

• KIEAE Journal
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• v.9 no.2
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• pp.17-26
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• 2009

High-rise and high-density apartment complexes have been built and supplied on a large scale in the 1st period New Town of metropolitan areas since the late 1980s. Recently it has become necessary to improve those apartment complexes which have blight problems for aging more than about 20 years accompanying simultaneity and a large scale. The purpose of this study is to analyze actual conditions of high-rise and high-density apartments in a view of sustainable regeneration. The contents and methods of this study are as follows. First, the concept of high-rise and high-density in domestic apartment developments were identified through review of literature and the law. Second, development conditions of Bundang new town and 1st period new town were studied. Third, the evelopment conditions of high-rise and high-density apartments in cases of 6 apartment complexes were analyzed from points of view of sustainable development by literature review and a field study. The results of this study are as follows. First, high-density range in domestic apartments can be conceptualized as 600 persons/ha. High-rise range in domestic apartments can be onceptualized as more than 11 stories under 30 stories. Second, characteristics and subjects based on actual conditions analysis could suggest on physio-environmental aspect and socio-economic aspect. Major characteristics and subjects of the physio-environmental aspect were 1.satisfaction of convenient facilities and public transportation service, 2.shortage of parking space, 3.uniform & blight of community facilities, 4.uniformed building layout, and 5.uniform pattern of unit plan and low flexibility by the bearing wall structure. And those of the socio-economical aspect were 1.satisfaction of current community, 2.increase and diversity of needs of the elderly by socio-demography change, 3.improvement of size and method of apartment complex development and 4.raising of economic-sufficiency.