• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1135-1140
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• 2016

The main challenge in designing wearable WBANs is to guarantee the balance of QoS demands in the network with the low power constraints of limited battery powered nodes. Low power devices implanted in or attached to the body should be designed to meet minimum energy requirements due to their limited battery life and be small in size to be easily wearable. In this paper, we propose a method for optimizing channel allocation method that is compatible with the IEEE 802.15.6 standard, enables the maximum amount of power charge at idle, guarantees the QoS of a WBAN, and provides the reliable date transmission between nodes and hubs in the network. Our extensive simulations will show that the method we propose not only maximizes the QoS in packet transmission but also improves the level of energy efficiency.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.1-6
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• 2015

We investigated green phosphorescent organic light-emitting diodes with stepwise doping to improve efficiency roll-off and operational lifetime by efficient distribution of triplet excitons. The host material which was 4,4,N,N'-dicarbazolebiphenyl (CBP) of bipolar characteristic that can control the carrier in emitting layer (EML). When the EML devided into four parts with different doping concentration, each devices shows various efficiency roll-off and lifetime enhancement. The distribution of the carrier and excitons in the EML can be confirmed by using stepwise doping structure. The properties of device C exhibited luminous efficiency of 51.10 cd/A, external quantum efficiency of 14.88%, respectively. Lifetime has increased 73.70% compared to the reference device.

• Polymer(Korea)
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• v.29 no.4
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• pp.357-362
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• 2005

As a new class of electroluminescent (EL) polymers, PPV-based polymers containing sulfone group in the main chain were synthesized through Witting polymerization reaction to control n-conjugation length and energy levels for predictable light emission and enhanced device performance. These EL polymers showed good solubility in common organic solvents and high thermal stability with initial decomposition temperature of ca. $400^{circ}$ and glass transition temperature around $200^{circ}C$ Emission colors were tuned from green to deep blue by reducing ${\pi}$-conjugated length between sulfone groups. It was also noted from the cyclic voltammetry (CV) measurements and semiempirical calculations that sulfone group with high electron affinity effectively lowered HOMO-LUMO energy levels to enhance EL device performance.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.627-641
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• 2006

Atmospheric $PM_{2.5}$ and $PM_{10}$ were measured to investigate their levels and water-soluble ions(${SO_4}^{2-},\;{NO_3}^-,\;{NO_2}^-,\;Cl^-,\;{NH_4}^+,\;Na^+,\;Ca^{2+},\;Mg^{2+},\;and\;K^+$) in Daegu between February 17 and April 18, 2006. Four Asian dust episodes during the period were examined for the influence of Asian dust on the particulate properties. Daily $PM_{2.5}\;and\;PM_{2.5-10}$ concentrations ranged between $10.83{\sim}136.76{\mu}g/m^3$ with a mean of $38.43{\mu}g/m^3$ and $16.13{\sim}409.13{\mu}g/m^3$ with a mean of $79.98{\mu}g/m^3$, respectively. For all measured ions the mean fractions of $PM_{2.5}\;and\;PM_{2.5-10}$ were 51.8% and 28.9% being lowered to 30.7% and 9.4%, respectively, during the dust episodes. Secondary ions (i.e., non-sea salt ${SO_4}^{2-},\;{NO_3}^-,\;and\;{NH_4}^+$) contributed 44.3% and 14.8% to $PM_{2.5}\;and\;PM_{2.5-10}$, respectively, with a decreased contribution during the episodes. The average equivalent ratio of ${NH_4}^+$ to the sum of ${SO_4}^{2-}\;and\;{NO_3}^-$ was 0.99 and 0.89 for $PM_{2.5}\;and\;PM_{2.5-10}$, respectively, indicating high source strength of $NH_3$ and its dominance in the neutralization of the acidic ions. Correlations and charge balance between ions suggest that neutralization of the acidic ions results in substantial depletions of carbonate both in $PM_{2.5}\;and\;PM_{2.5-10}$ and chloride only in $PM_{2.5}$.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.3
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• pp.73-80
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• 2011

This study aims to develop furniture industry in eastern district of Gangwondo and a city of Gangneung and Donghae. Case study on furniture complex in Asahikawa, Japan and survey of furniture companies in Gangneung and Donghae city were implemented for understanding of present state, followed by analysis of problems. It can be summarized as follows. First, the basic operation method of Japanese furniture industry is to keep a balance between industry and academy. Universities or centers are in charge of education and fostering talents, such as allowing to promote and to sell products in design center gallery while corporations support it by lending expensive devices and conducting strength test analysis. Second, according to the survey of furniture companies in Gangneung, many difficulties in products development such as a shortage of designer, method, creative design were discovered. With respect to education and human force fostering, education for design and e-commerce were not sufficient, also marketing section has a problem with limited space for display and selling. Corporate support section is facing problems in receiving raw materials, aging of facilities, manufacturing and management methods. Consequently, it is considered that academic and industrial sections should implement their own roles by forming a bilateral network which connects local universities, high schools, relevant organization in the city and providence and furniture manufacturing companies to companies' product development, human force fostering and marketing in an attempt to activate the furniture industry in this area.

• Journal of Digital Contents Society
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• v.11 no.4
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• pp.463-471
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• 2010

In the management of a wastewater treatment plant which is a combination system of physical, chemical, and biological processes, computer simulator is an indispensable part for analysis of the operation status and evaluation of the treatment performance due to its fast computing speed. As an application software carrying out the data input-output operations and the mathematical calculations of the models, simulator is to be a powerful tool for estimating the treatment reaction and calculating mass balance of substrates, microorganisms, and chemicals within the treatment system in a given condition. Qualitative and quantitative prediction of treatment performance provides the plant manager with validity of decision-making through implementing modeling and simulation as a role of knowledge-based expert system in charge of automation and control. This paper shows the proceeding of design and development of the "WEC-Sim" software which is owned the various functions of data acquisition, monitoring, simulation, and control.

• Journal of the Korean Dietetic Association
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• v.5 no.2
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• pp.117-127
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• 1999

This study was carried out to provide the improvable way of foodservice management to dietitian in the elementary schools. For this purpose the serving pattern of food, menu planning, nutrition education, leftover management and difficulties in foodservice were investigated. The survey was conducted through questionnaires, which were collected from 249 dietitions randomly selected in Taejon and Chung Nam. Data were analyzed by SAS program. The main results of this study are as follows. The children in Taejon took foods in the class room(65.7%) and those in Chung Nam in the dinning hall(89.9%)(p<0.01). In menu planning the balance of nutrition(42.6%) was mainly considered and then food preference(19.7%), variety of menus(16.1%), food cost(16.1%), composition of food color, taste and texture(3.2%), skills of food making(1.6%) and the number of students(0.8%). They referred cooking magazines(47.7%), the previous menu(42.2%), children's opinion(7.2%) for planning menu. The insufficiency of implements and devices for food(24.1%) and lack of season's food(20.4%) were indicated as difficulties in their job. 34.5% of dietitians used a standard menu, 79.5% investigated food preference of children, 74.3% evaluated taste of foods before serving, and 80.7% regularly checked leftover. The major reason for leftover was careless of the teacher in charge in Taejon and bad taste of foods nutrition in Chung Nam(p<0.001). 98.5% of them answered that they had the responsibility for nutrition education in elementary school. They had a hard time in relationship with the staffs in school(40.6%) and employees for food(39.8%), and lack of market information(38.2%). To efficiency of dietitian's work can be enhanced by reflecting the results of children's food preference and leftover, by using standard cooking method and proper cooking utensil, and by performing nutrition education for children by themselves.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.425-434
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• 2017

The purpose of this study was to explore the relationship of gender discrimination consciousness, work-family conflict and facilitation, and turnover intention of married female hospital nurses. The participants included 101 married female nurses at hospitals in S city. Gender discrimination consciousness was higher, benevolent sexism was higher than hostile sexism. The nurses under 40, had one child and worked within 5 years had higher work-family conflict. Turnover intension was significantly higher when the nurses were under 40 (t=3.66, p<.001), had no children (F=5.76, p=.004), and were staff and charge nurses (F=5.86, p=.004). Hostile sexism had correlated to family-to work conflict and facilitation. Turnover intention had a positive correlation to work-to family conflict and family-to work conflict. Through this study, we were understand the relationship of gender discrimination consciousness, work-family conflict and facilitation, turnover intension of married female hospital nurses, and for work-family balance, it was found that more study is needed.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.57-63
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• 1996

The compound titanium (III) pyrophosphate, KTiP2O7 has been prepared and the crystal structure of the compound has been determined by the X-ray diffraction techniques. It crytallizes in the space group P21/a of the monoclinic system with four formula units in a cell of dimensions a=8.210(3), b=10.292(2), c=7.434(1)Å and β=106.71(2)°. The structure consists of the framework possessing corner-sharing octahedral TiO6 and pyrophosphate groups. As a result, a tunnel structure has been constructed and the K+ cations reside inside the tunnel. KTiP2O7 is isostructural with other trivalent metal pyrophosphates such as KAlP2O7 and RbTiP2O7 but the size difference of the alkali metals causes the variation in the structure. The classical charge balance of the compound can be described as [K+][Ti3+][P24O74-].

• Journal of the Mineralogical Society of Korea
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• v.4 no.2
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• pp.99-107
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• 1991

Three fully dehydrated fully Rb+-exchanged zeolite A single crystals have been prepared by the reduction of all Na+ ions in dehydrated Na12-A by rubidium vapor at various experimental conditions (220 $\leq$ T $\leq$ 33$0^{\circ}C$, 2 $\leq$ t $\leq$24 hours, and 0.1 $\leq$ PRb $\leq$ 1.1 Torr). Their structures were determined by single-crystal X-ray diffraction methods in the space group {{{{ RHO }}m3m (a=12.245(3) A) at 22(1)$^{\circ}C$. In these structures 12.6(2) to 13.5(2) Rb species are found per unit cell, more than the 12 Rb+ ions needed to balance the anionic charge of the zeolite framework, indication that the sorption of Rb0 has occurred. In each structure, three Rb+ ions per unit cell are located at the centers of 8-rings. Beyond that, the fractional occupancies observed are simply explained by two unit cell arrangments. In one, two Rb+ ions are in the sodalite unit near opposite 6-rings, six are in the large cavity near 6-ring, and one is in the large cavity near a 4-ring. In the other, three Rb species in the sodalite cavity (forming a triangle 3.7 A on an edge) each bond (3.4 A) through a 6-ring to an Rb species in the large cavity to give an (Rb6)4+ cluster of symmetry 3m (C3V). Five additional Rb+ ions fill the remaining large-cavity 6-ring sites.