• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.2
• /
• pp.545-563
• /
• 2015

Energy harvesting (EH) and network coding (NC) have emerged as two promising technologies for future wireless networks. In this paper, we combine them together in a single system and then present a time switching-based network coding relaying (TSNCR) protocol for the two-way relay system, where an energy constrained relay harvests energy from the transmitted radio frequency (RF) signals from two sources, and then helps the two-way relay information exchange between the two sources with the consumption of the harvested energy. To evaluate the system performance, we derive an explicit expression of the outage probability for the proposed TSNCR protocol. In order to explore the system performance limit, we formulate an optimization problem to minimize the system outage probability. Since the problem is non-convex and cannot be directly solved, we design a genetic algorithm (GA)-based optimization algorithm for it. Numerical results validate our theoretical analysis and show that in such an EH two-way relay system, if NC is applied, the system outage probability can be greatly decreased. Moreover, it is shown that the relay position greatly affects the system performance of TSNCR, where relatively worse outage performance is achieved when the relay is placed in the middle of the two sources. This is the first time to observe such a phenomena in EH two-way relay systems.

• Journal of Nutrition and Health
• /
• v.30 no.3
• /
• pp.360-369
• /
• 1997

Food/nutrition related views, beliefs, attitudes, and behaviors were investigated for three hundred randomly selected men and women, aged 20-60 years, residing in Seoul metropolitan area. Food/nutrition views, attitudes, and beliefs were found to vary greatly between groups of different age, sex, education and income level. Adults of 20-35 years of age showed significantly less strong views about keeping traditional food habits, while exhibiting a significantly high level of acceptance towards the use of convenience foods as compared to the adults aged 36 years or older. Food safety was found to be a major concern to most of the subjects accounting 69.7% for pesticides residues in fresh produce items, 94.7% for food additives in processed food, and 56.3% for food poisoning in foods eaten outside of the home. Male adults aged 45 years or older showed a strong tendency to rely on a few promotional food products for the maintenance of their health and for them the development and implementation of a sensible feed nutritin/health education program including a way to avoid nutrition quackery might be beneficial. Eighty percent of the subjects were found to read food labels with higher rates shown among young adults and females. Due to the virtual absence of nutrition labeling however, the percentage of subjects who idicated that they are looking for the information on nutrient content was low (<10%) compared to the rates for other informations such as date of manufacture(80.2%), expiration data(55.8%), ingredients(40.9), and additives(40.9%). Ninety one percent of the subjects indicated that they would like to see the sources for nutrition label the nutritional value of the foods. The top five most frequently (68.3%), food packages(50.7%), and radio(43.3%). Health professionals such as physicians, nurses, and nutritionists/dietitians were utilized less frequently as sources of nutrition information than lay sources, with reported rate of only 38%, 22%, and 0.7%, respectively. These results collectively suggest that strategies are to be developed to provide accurate nutrition information to adults.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.46.2-46.2
• /
• 2017

Atmospheric propagation effects at millimeter wavelengths can significantly alter the phases of radio signals and reduce the coherence time, putting tight constraints on high frequency Very Long Baseline Interferometry (VLBI) observations. In previous works it has been shown that non-dispersive (e.g. tropospheric) effects can be calibrated with the frequency phase transfer (FPT) technique. The coherence time can thus be significantly extended. Ionospheric effects, which can still be significant, remain however uncalibrated after FPT, as well as the instrumental effects. In this work, we implement a further phase transfer between two FPT residuals (i.e. so-called FPT2) to calibrate the ionospheric effects based on their frequency dependence. We show that after FPT2, the coherence time at 3 mm can be further extended beyond 8 hours, and the residual phase errors can be sufficiently canceled by applying the calibration of another source, which can have a large angular separation from the target (> $20{\circ}$). Calibrations for all-sky distributed sources with a few calibrators are also possible after FPT2. One of the strengths and uniqueness of this calibration strategy is the suitability for high frequency all-sky survey observations including very weak sources. We discuss the introduction of a pulse calibration system in the future to calibrate the remaining instrumental effects and allowing the possibility of imaging the source structure at high frequencies with FPT2, where all phases are fully calibrated without involving any sources other than the target itself.

• Journal of Nutrition and Health
• /
• v.41 no.8
• /
• pp.860-869
• /
• 2008

The purposes of this study were to investigate use patterns of nutrition information service of 50-and-older adults and analyze the differences in use patterns of nutrition information service according to their socio-demographic variables. The survey was conducted with 500 adults aged 50-and-over living in Seoul between March 28 and April 10, 2007. A total of 401 questionnaires were used for analysis (use rate 80.2%) and the statistical data analyses were completed using SPSS Win (ver 12.0). The main results of this study were as follows. First, most respondents (73.3%) realized the need for nutrition counseling or education. However, 65.3% of respondents have little experience in nutrition counseling or education. Second, the most preferred methods of nutrition counseling or education were field trips (27.7%), counseling in hospitals/public health centers (23.4%), cooking classes (23.2%). And the most often cited sources of nutrition information were TV/radio (66.6%) and newspapers/magazines/books (41.6%). Third, sociodemographic variables such as sex, age, education level, occupations were significantly related to methods of nutrition counseling or education. And variables such as age, education level, occupations were significantly related to often cited sources of nutrition information. Also sex, age, education level, occupations were significantly related to needs for nutrirtion information service.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.8 no.3
• /
• pp.27-33
• /
• 2009

Content used in mashups is typically obtained from a third party source through a public interface or API (web services). Other methods of obtaining content for mashups include Web feeds (e.g. RSS or Atom), and screen scraping. A mashup or meshup Web application has two parts: A new service delivered through a Web page, using its own data and data from other sources. The blended data, made available across the Web through an API or other protocols such as HlTP, RSS, REST, etc. There are many types of mashups, such as consumer mashups, data mashups, and Business Mashups. The most common mashup is the consumer mashup, which are aimed at the general public. Examples include Google Maps, iGuide, and RadioClouds. 4D Wall-map display is data mashups combine similar types of media and information from multiple sources into a single representation. This technology focus data into a single presentation and allow for collaborative action among ITS-related information sources.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.11 no.1
• /
• pp.10-15
• /
• 2012

Ultra wideband (UWB) technologies have been developed to exploit a new spectrum resource in substances and to realize ultra-high-speed communication, high precision geo-location, and other applications. The energy of UWB signal is extremely spread from near DC (Direct Current) to a few GHz. This means that the interference between conventional narrowband systems and UWB systems is inevitable. However, the interference effects had not previously been studied from UWB wireless systems to conventional wireless systems sharing the frequency bands such as broadcasting system. This paper experimentally evaluates the interference from two kinds of UWB sources, namely an orthogonal frequency division multiplex UWB source and an impulse radio UWB source, to a broadcasting transmission system. The S/N ratio degradation of broadcasting system is presented. From these experimental results, we show that in all practical cases UWB system can be coexisted 35m distance in-band broadcasting network.

• The Research Journal of the Costume Culture
• /
• v.8 no.2
• /
• pp.183-196
• /
• 2000

The purpose of this study was to identify cosemetics purchasing behavior of male college students by clothing involvement. A questionnaire was administered to 246 male collage students living in Taegu and Seoul during September of 1999. Data were analyzed by using frequency, cross tabulation, t-test, χ²-test and factor analysis. The results of this study were as follows : First, the consumers are classified into two categories by clothing involvement ; 65.5% of the highly involved consumers and 34.5% of the lowly involved consumers. Second, the factors of selecting cosmetics were fragrance, quality and price. Third, the major information sources of cosmetics are TV, magazines, outdoor advertisements, newspapers, subway, radio and internet in order of importance. Fourth, high clothing involved group was more fashion oriented and showed more impulsive purchasing attribute.

• Publications of The Korean Astronomical Society
• /
• v.32 no.1
• /
• pp.275-279
• /
• 2017

The AKARI Deep Field South (ADF-S) is a large extragalactic survey field that is covered by multiple instruments, from optical to far-IR and radio. I summarise recent results in this and related fields prompted by the release of the Herschel far-IR/submm images, including studies of cold dust in nearby galaxies, the identification of strongly lensed distant galaxies, and the use of colour selection to find candidate very high redshift sources. I conclude that the potential for significant new results from the ADF-S is very great. The addition of new wavelength bands in the future, eg. from Euclid, SKA, ALMA and elsewhere, will boost the importance of this field still further.

• Proceedings of the Korea Society of Information Technology Applications Conference
• /
• 2005.11a
• /
• pp.187-190
• /
• 2005

Ultra wideband (UWB) technologies have been developed to exploit a new spectrum resource in substances and to realize ultra-high-speed communication, high precision geolocation, and other applications. The energy of UWB signal is extremely spread from near DC to a few GHz. This means that the interference between conventional narrowband systems and UWB systems is inevitable. However, the interference effects had not previously been studied from UWB wireless systems to conventional mobile wireless systems sharing the frequency bands such as WCDMA system. This paper experimentally evaluates the interference from two kinds of UWB sources, namely a direct-sequence spread-spectrum UWB source and an impulse radio UWB source, to a WCDMA digital transmission system. The average frame error rate degradations are presented. From these experimental results, we show that in all practical cases UWB system can coexist with WCDMA terminal without causing any dangerous interference.

• Journal of Astronomy and Space Sciences
• /
• v.29 no.1
• /
• pp.85-91
• /
• 2012

Optical interferometry and polarimetry have separately provided new insights into stellar astronomy, especially in the fields of fundamental parameters and atmospheric models. We present: scientific justifications for "full-Stokes" optical interferometric polarimetry (OIP); updated instrument requirements; preliminary beam combiner designs; polarimeter design; end-to-end OIP data reduction; and realistic reimaged full-Stokes models of Be stars with a suitable number of telescopes plus noise sources. All of this work represents preliminary research to construct an OIP beam combiner.