• The korean journal of orthodontics
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• v.46 no.3
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• pp.155-162
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• 2016

Objective: The aim of this study was to investigate whether labial tooth inclination and alveolar bone loss affect the moment per unit of force ($M_t/F$) in controlled tipping and consequent stresses on the periodontal ligament (PDL). Methods: Three-dimensional models (n = 20) of maxillary central incisors were created with different labial inclinations ($5^{\circ}$, $10^{\circ}$, $15^{\circ}$, and $20^{\circ}$) and different amounts of alveolar bone loss (0, 2, 4, and 6 mm). The $M_t/F$ necessary for controlled tipping ($M_t/F_{cont}$) and the principal stresses on the PDL were calculated for each model separately in a finite element analysis. Results: As labial inclination increased, $M_t/F_{cont}$ and the length of the moment arm decreased. In contrast, increased alveolar bone loss caused increases in $M_t/F_{cont}$ and the length of the moment arm. When $M_t/F$ was near $M_t/F_{cont}$, increases in Mt/F caused compressive stresses to move from a predominantly labial apical region to a palatal apical position, and tensile stresses in the labial area moved from a cervical position to a mid-root position. Although controlled tipping was applied to the incisors, increases in alveolar bone loss and labial tooth inclination caused increases in maximum compressive and tensile stresses at the root apices. Conclusions: Increases in alveolar bone loss and labial tooth inclination caused increases in stresses that might cause root resorption at the root apex, despite the application of controlled tipping to the incisors.

• Journal of the Korean Home Economics Association
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• v.43 no.11 s.213
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• pp.127-140
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• 2005

Sanitary management performance and knowledge of employees in hospital food service was evaluated by survey questionnaire to improve their sanitary management performance, analyse the weak points of sanitary management, and determine more practical and efficient alternatives of sanitation education. For this study, we selected 6 dieticians and 250 employees working in the six general hospitals larger than 400 beds in Gyeonggi and Incheon area. The questionnaire consisted of three parts: general subjects in the nutrition division of hospitals, sanitation education of dieticians, and sanitary management performance and knowledge of employees. The average ratio of HACCP related equipment and facilities of the target hospitals was relatively high at $86.5\%$. The number of sanitation education was 1.99 times/month by regular schedule and 6.47 times/month by occasional schedule. The average dietician's inspection time of cooking was 178.77 minutes/day. The average point of sanitary management performance was 4.62/5.0, showing a relatively high grade. In each region of sanitary management performance, food treatment sanitation was marked with the highest point, at 4.85, fellowed by cleaning and sterilizing sanitation at 4.65, personnel sanitation at 4.61 point and device and utensil sanitation was ranked with the lowest point at 4.53. Sanitary management performance was affected by the number of occasional education which was highest at 6-10times/month. The mean score of sanitary knowledge was 11.17/15.0. The assigned position, type of employment, status, working career and number of occasional education affected the mean score of sanitary knowledge of employees significantly. Sanitary knowledge of employees was highest in the case that occasional education was peformed at 6-10 times/month. There was no correlation between the sanitary management performance and sanitary knowledge of employees. In contrast, there were correlations between sanitary management performance and dietician's inspection time of cooking and number of employees.

• Journal of Communications and Networks
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• v.14 no.2
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• pp.162-168
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• 2012

This paper considers the scenario in which a set of nodes share a common channel. Some nodes have a rechargeable battery and the others are plugged to a reliable power supply and, thus, have no energy limitations. We consider two source-destination pairs and apply the concept of cognitive radio communication in sharing the common channel. Specifically, we give high-priority to the energy-constrained source-destination pair, i.e., primary pair, and low-priority to the pair which is free from such constraint, i.e., secondary pair. In contrast to the traditional notion of cognitive radio, in which the secondary transmitter is required to relinquish the channel as soon as the primary is detected, the secondary transmitter not only utilizes the idle slots of primary pair but also transmits along with the primary transmitter with probability p. This is possible because we consider the general multi-packet reception model. Given the requirement on the primary pair's throughput, the probability p is chosen to maximize the secondary pair's throughput. To this end, we obtain two-dimensional maximum stable throughput region which describes the theoretical limit on rates that we can push into the network while maintaining the queues in the network to be stable. The result is obtained for both cases in which the capacity of the battery at the primary node is infinite and also finite.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.95-103
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• 2017

Ramie (Boehmeria nivea) is a perennial herbaceous plant belonging to the family Urticaceae. It was used in folk remedies for diuretic or anti-pyretic purposes and as an hepatoprotective, anti-oxidant, and anti-inflammation agent. In this study, we investigated the composition of free sugars, amino acids, fatty acids, organic acids, and total polyphenol contents in parts of ramie (root, stem, and leaf) and different harvest areas (10 areas). Overall, free sugars were found as sucrose, glucose, fructose, and galactose at concentrations ranging from 24.5 to 1173.8 mg/g. Amino acids lysine, threonine, tyrosine, phenylalanine, and histidine were detected at concentrations of 33.8 to 3735.3 mg/g. Major fatty acids were linoleic acid, palmitic acid, and linolenic acid at concentrations of 7.3 to 364.4 mg/g. In organic acids, the concentration of malic acid was highest of all with 672.2 mg/g. The content of free sugars, amino acids, fatty acids, organic acids, and total polyphenol was higher in leaves than in roots and stems. In contrast, the total polyphenol content was higher in roots with 33.7 - 219.4 mg/g than in leaves or in stems. As seen in collecting region, the contents of free sugars, amino acids, fatty acids, organic acids, and total polyphenol of Bn-33, 39, 55, 65, and 90 were higher than other samples. Chemical compositions of different parts of ramie are important factors to consider in manufacturing functional foods. The results of this study provide fundamental information on the chemical compositions of ramie parts and would help develop new functional foods from ramie leaves or the whole plant.

• Bulletin of the Society of Naval Architects of Korea
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• v.2 no.1
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• pp.9-14
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• 1965

Ship designers make every efforts to get faster ships in accordance with the development of the Naval Architecture. But for the speed lying over factor length ratio 2.5-3.0, we could put a powerful engine into the conventional round bottom displacement type vessels, but it is very difficult in view point of economy, weight and volume. The principal cause of these speed obstacles is the wave making resistance and researchers are trying to decrease this resistance. One of the resolving ways, planing hulls were applied to small high boats. Planing hull's advantage is not restricted to speed, but the workmanship of the planing hull is easier than those of displacement type vessels of round bottom. Planing hull, therefore, are widely applicable to the intermediate speed boats, which don't have enough high speed to take planing advantage, as well as high speed boats. We will discuss related phenomena of the planing hull in details and this paper we particularly interested in the interjection point(speed length ratio 3.0-3.5 by Mr. D. De Groots) between semi-planing and full planing hulls on the resistance characteristic curve. The paper by Prof. Keuck Chun Kim, "Some Characteristics of Straight Framed V-bottom Hull Forms", Journal of the society of Naval Architects of Korea, Vol.1, No.1, Dec.5, 1964, is referred to the V-bottom hull forms belonging to low speed region and determines practical applicable limit of the speed length ratio combined with construction costs, under which are still used by large commercial vessels. This is the interesting contrast between his and authors. We will further discuss the speed length ratio which is considered as a beginning point to planing effect. For this analysis, we choose 3 model ships: Model (1) and (2) have the same principal dimensions, model 3 varied dimension. Model (1) is full-planing hull, (2) is semi-planing hull and (3) is complete planing hull. They are aimed to collect proper design data for purposed ships.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.70-78
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• 2000

In applying high-${\underline{T_c}}$ superconducting material to microwave devices, Uncertainty of electromagnetics of high-${\underline{T_c}}$ superconductor(HTS) and the temperature dependence of the substrate fits with HTS thin film cause difficulty in realization of such antenna for industrial applications. It must be noted to characteristic the HTS antenna in contrast with normal conducting counterpart for this real application. In this paper, a comparative study between HTS microstrip antennas and gold antennas was reported in terms of the return loss, the characteristic impedance, efficiency, and other various characteristics. HTS thin films were $YBa_2Cu_3O_{7-x}$ (YBCO) on MgO substrates. Superconducting microstrip antennas used in this work were to directly inset a microstrip transmission line into the 50 ${\Omega}$ region of the radiating patch. Measurement results of HTS antennas and gold antennas showed that usable antennas can be made using this architecture.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.40-47
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• 2009

A motion adaptive video noise reduction scheme is proposed by cascading a temporal filter and a spatial filter. After a noise-robust motion detection is performed with a pre-spatial filter, the strength of the motion adaptive temporal filter is controlled by the amount of temporal movement. In order to fully utilize the temporal correlation of video signal, noisy input image is processed first by the temporal filter, therefore, image details of temporally stationary region are quite well preserved while undesired noises are suppressed. In contrast to the pre-spatial filter used for the robust motion detection, the cascaded post-spatial filter removes the remained noises by considering the strength of the temporal filter and the spatial self-similarity search results obtained from the pre-spatial filter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.7
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• pp.81-88
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• 2004

In case of mechanical down tilting, a horizontal pattern is distorted and beam width widens whenincreasing tilt angle, which causes an expansion of hand off region and burden base station equipment. In contrast, electrical down tilting has advantage that horizontal HPBW is kept constant with down tilting. In this paper, based on a phased array technology, dual polarized base station antenna with electrical down tilting was developed at 800MHz band. The antenna has down tilting range of 0$^{\circ}$ to 14$^{\circ}$, and 15㏈i gain. We use stacked microstrip patch as a radiated element and apply balanced feed technique to improve isolation between ports and discrimination of cross polarization. The effect of electrical down tilting was verified by field test.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.223-229
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• 2010

This study is to analyze location conditions for erosion control dams to be constructed in Chungcheongnam-do, Daejeon Metropolitan City, Chungcheongbuk-do and Gyeongsangbuk-do in order to establish proper conditions for erosion control dams in the future. 199 sites where erosion control dams are expected to be built in 2010 were chosen and investigated in terms of 12 factors including basin area, basin slope, and landslide risk. The results showed that erosion control dams for Chungcheongnam-do and Daejeon Metropolitan City are mostly impermeable gravity dams mainly composed of concrete. In contrast, Chungcheongbuk-do and Gyeongsangbuk-do are increasing the number of permeable or compound erosion control dams. Basin analysis at planned erosion control dam sites showed that at least 44.5% of the total area has high landslide risk. Gyeongsangbuk-do had the largest basin area for erosion control dam sites at 157.3ha, followed by Chungcheongbuk-do at 64.4ha and Chungcheongnam-do at 54.8ha. Analysis of sand deposits in the Chungcheongnam-do erosion control dam built in 2010 confirmed an average deposit of 971.8m3. The sand deposit capacity and amount of sediment control for erosion control dams have a very low correlation with basin area or flow path slope, and this needs to be addressed in future sand deposit capacity designs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.918-923
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• 2009

In this paper, a design method of the compact narrow band filter on the microstrip board is proposed using complementary split-ring resonators(CSRRs). The design technique of this filter is based on cascading filter stages consisting of the combination of circular CSRRs, capacitive gaps between patches, and inductive grounded stubs with the meander configuration. By these means, it was possible to get the nearly symmetric frequency responses, adjustable bandwidths, compact sizes. And also excellent characteristic of the out-of-band rejection is achieved in contrast to the conventional filter design technique. The measured insertion shows good results about -4.0dB at the center frequency($f_0=1GHz$) and passband return loss is less than -9.4dB. The 3dB fractional bandwidth(FBW) is approximately 4%. The results of the frequency response measured on the fabricated band pass filter substrate show satisfactory agreement with the simulated frequency responses by the HFSS in the region of interest.