• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.327-335
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• 2003

The commercially available neutron survey meter, the REM500, which uses a tissue equivalent proportional counter (TEPC) and the self-constructed TEPC were used to determine the microdosimetric quantities of several neutron calibration fields at Korea Atomic Energy Research Institute (KAERI). Microdosimetric spectra, absorbed dose, dose equivalent as well as quality factor were derived and compared with several neutron fields which were produced by using the shadow objects to make neutron scattered and being used as a kind of realistic neutron calibration fields at KAERI. The response of REM500 as a function of mean energy was evaluated with these neutron fields using the counts measured and the predetermined reference value. The response of the self-made TEPC and the REM500 was compared using one of the neutron calibration filelds of a $^{252}Cf$ source. The reference quantities of scattered neutron calibration fields were determined using a Bonner Sphere (BS). The value of frequency-mean lineal energy, dose-mean lineal energy and quality factor of two $^{252}Cf$ sources (unmoderated and $D_2O$ moderated) were determined to check the differences in the reference neutron fields between KAERI and Pacific Northwest National Laboratory (PNNL, USA) and the results were in good agreement within 1%. It means that there is no big difference in dosimetric quantifies of neutron calibration fields of two laboratories.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.194-203
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• 2014

Yam (Dioscorea batatas) is widely consumed as functional food for health promotion mainly in East Asia countries. We assessed whether yam root (tuber) or bark (peel) extracts stimulated the activity of osteoblasts for osteogenesis. MC3T3-E1 cells (mouse osteoblasts) were treated with yam root extracts (water or methanol) (study I) or bark extracts (water or hexane) (study II) within $0{\sim}10{\mu}g/mL$ during the periods of osteoblast proliferation (5~10 day), matrix maturation (11~15 day) and mineralization (16~20 day) as appropriate. In study I, both yam root water and methanol extracts increased cell proliferation as concentration-dependent manner. Cellular collagen synthesis and alkaline phosphatase (ALP) activity, both the indicators of bone matrix protein and inorganic phosphate production for calcification respectively, were also increased by yam root water and methanol extract. Osteoblast calcification as cell matrix Ca and P accumulation was also increased by the addition of yam root extracts. In study II, yam bark extracts (water and hexane) increased osteoblast proliferation and differentiation, as collagen synthesis and ALP activity and osteoblast matrix Ca and P deposition. The study results suggested that both yam root and bark extracts stimulate osteogenic function in osteoblasts by stimulating bone matrix maturation by increasing collagen synthesis, ALP activity, and matrix mineralization.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.649-660
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• 2005

The effects of Lactobacillus buchneri 40788 and buffered propionic acid on preservation, intake and digestibility of alfalfa (Medicago sativa) and timothy (Phleum pratense) hay were investigated. During baling, forages were treated with L. buchneri 40788 (1.2${\times}$10$^6$ CFU/g) as a liquid (LLB) or as a granular preparation (GLB), with buffered propionic acid (10 mL/kg, BPA), or left untreated (control). Triplicate 500 kg round bales of each treatment were put up at two moisture levels for each forage: 17%${\pm}$0.33% and 20%${\pm}$0.30% for timothy and 17%${\pm}$0.20% and 19%${\pm}$0.27% for alfalfa (mean${\pm}$SD). Bales were sampled for chemical and microbiological analyses after 0, 30 and 60 d of storage. Compared to controls, all preservatives reduced (p<0.05) heating of both forages at all moisture levels with the exception of alfalfa baled at 19% moisture. After 60 d of storage, GLB reduced (p<0.05) moulds in 17% timothy hay as compared to other treatments, but at 20% moisture, moulds were reduced in LLB- and BPA-treated timothy as compared to controls. In alfalfa at 17% moisture, total bacteria were lower (p<0.05) in GLB-treated bales than LLB or control bales, but yeast and total bacteria were only reduced in BPA-treated alfalfa at 19% moisture. In situ DM disappearance of timothy (both moisture levels) and alfalfa (19% moisture level) increased (p<0.05) with LLB treatment compared to control. Digestibility of both forages did not differ (p>0.05) among treatments, however, voluntary DM intake of LLB-treated timothy (1.32 kg/d) was 22.3% higher (p<0.05) than control, and 14.1% higher than BPA-treated timothy. Treating timothy and alfalfa hay with L. buchneri 40788 or buffered propionic acid may improve the nutritive value of the hay when baled at 17 to 20% moisture.

• Korean Journal of Adult Nursing
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• v.14 no.3
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• pp.390-400
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• 2002

Purpose: This study was to prepare the basic data for prevention of colorectal cancer and protection against its spread. Method: The subjects for the study were 204 patients with colorectal cancer from the G.S. wards of five general hospitals in Busan for the period of June 1 to September 1, 2001. The instrument used was a questionaire which was developed by Junho Shin(1995). The data was analyzed by descriptive statistics, McNemar test, ${\chi}^2$ test, paired t-test, and ANOVA. Result: 1. 57% of the studied subjects were male, 42.7% were more than 60 years old, 54.9% were of standard physique, 49.5% were the Buddhists, 50.5% were the middle or high school graduates, 83.8% were city dwellers, 48% were jobless, 69.6% had no-history of alimentary disease, 44.1% had no-family history of cancer, 82.8% were married. 2. Constipation (${\chi}^2=36.45$, p=0.0001) in clients showed a significant positive association for the prediagnosed, but diarrhea(${\chi}^2=3.947$, p=0.047) showed a significant positive association for the post-diagnosed. The preference for high seasonings(t=6.23, p=0.0001) and animal fat (t=8.35, p=0.0001) was higher significantly in the pre-diagnosed, but physical activities(${\chi}^2=30.22$, p=0.0001), an eutrophic or tonic medicine(${\chi}^2=30.22$, p=0.0001), was of and vegetables(t=-6.20, p=0.0001) was higher significantly in the post-diagnosed. 3. There were significant differences in the life style of the pre-diagnosed according to the general characteristics except religion. Conclusion: Results of the above study reveal we should be very sensitive to the change of defecation styles and consider the necessity of improving life styles as regards eating habits. When an education program is developed, the general characteristics of the subjects need to be considered.

• Structural Engineering and Mechanics
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• v.64 no.4
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• pp.413-426
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• 2017

Probabilistic methods are used in engineering where a computational model contains random variables. The proposed method under development: Direct Optimized Probabilistic Calculation (DOProC) is highly efficient in terms of computation time and solution accuracy and is mostly faster than in case of other standard probabilistic methods. The novelty of the DOProC lies in an optimized numerical integration that easily handles both correlated and statistically independent random variables and does not require any simulation or approximation technique. DOProC is demonstrated by a collection of deliberately selected simple examples (i) to illustrate the efficiency of individual optimization levels and (ii) to verify it against other highly regarded probabilistic methods (e.g., Monte Carlo). Efficiency and other benefits of the proposed method are grounded on a comparative case study carried out using both the DOProC and MC techniques. The algorithm has been implemented in mentioned software applications, and has been used effectively several times in solving probabilistic tasks and in probabilistic reliability assessment of structures. The article summarizes the principles of this method and demonstrates its basic possibilities on simple examples. The paper presents unpublished details of probabilistic computations based on this method, including a reliability assessment, which provides the user with the probability of failure affected by statistically dependent input random variables. The study also mentions the potential of the optimization procedures under development, including an analysis of their effectiveness on the example of the reliability assessment of a slender column.

• Ocean and Polar Research
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• v.29 no.2
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• pp.123-134
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• 2007

Distribution patterns of sandy bottom macrobenthic communities were studied around the Hupo coastal area. The seasonal surveys were conducted at 15 chosen sites within a depth range of 10 to 50 m along 10 km of the coastline using a Smith-McIntyre grab $(0.05\;m^2)$ in 2005. Overall depth distribution following the direction of the offshore become deeper parallel to the coastline. A total of 319 macrobenthic species were sampled with a mean density of $1,972\;ind./m^2$, and mean biomass was 82.5 wet-weight $g/m^2$. The major individual-dominant species were three polychaetes Spiophanes bombyx ($436\;ind./m^2$), Scoletoma longifolia ($250\;ind./m^2$) and Magelona japonica ($170\;ind./m^2$), and bivalve Adontorhina subquadrata ($73\;ind./m^2$). Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray-Curtis similarity identified 2 major station groups which corresponded to macrobenthic faunal assemblages and their characteristic species. In addition, environmental conditions were significantly different between station groups. Group I contained mostly 20 and 50 m deep sites and was associated with sandy mud. Group I was characterized by high abundance of S. bombyx, S. longifolia, A. subquadrata. It was divided into two sub-groups (I-I and I-II) in relation to depth. Sub-group I-I was associated with deeper sites than sub-group I-II. Group II included mostly inshore area shallower than 15 m and was associated with coarse and medium sand. Group II was characterized by Lumbrinerides hayashii and Urothoe grimaldii japonica.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1613-1621
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• 2015

This paper analyzes the rate adaptation scheme and suggests applicable strategy of the MCS(Modulation and Coding Scheme) for improving DCF throughput in the IEEE 802.11ad and 802.11ad wireless LAN. IEEE 802.11ac and 802.11ad wireless LAN provide MCS technique that dynamically adjusts modulation level and code rate to the time-varying channel conditions in order to obtain considerably high data rates. But these standards did not provide rate adaptation algorithm, so this paper surveyes rate adaptation algorithm and suggests MCS scheme applied to IEEE 802.11ac and 802.11ad wireless LAN. Specially A MAC(Medium Access Control) layer throughput is evaluated over error-prone channel in the IEEE 802.11ac-based wireless LAN. In this evaluation, DCF (Distributed Coordination Function) protocol and A-MPDU (MAC Protocol Data Unit Aggregation) scheme are used. Using theoretical analysis method, the MAC saturation throughput is evaluated with the PER (Packet Error Rate) on the condition that the number of station, transmission probability, the number of parallel beams and the number of frames in each A-MPDU are variables.

• Journal of the Korean Regional Science Association
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• v.15 no.2
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• pp.21-38
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• 1999

This paper is concerned with analyzing the role of Northeast Asia intercity networks in Northeast Asia in creating regional networks. For the purpose of this paper, we have followed Choe's (1996) definition of Northeast Asia which includes the Russian Fat East, the Northeast region of China, South Korea, North Korea and Japan. The central hypothesis of the paper is that the geopolitical conditions of Northeast Asia compared for example with Southeast Asia, favor bilateral rather than multilateral linkages between nation states. In these circumstances, it is our hypothesis that cities will play an important role in developing a "local image" of regio-nalism and intercity networks. In order to analyze this hypothesis, the paper is divided into three parts. Part A analyzes the emerging urban system of the Northeast Asia region using Choe's concept of the BESETO corridor and updating his data from the late 1980s to the mid 1990s just prior to the financial crisis. This analysis is further supported by the analysis of economic and transportation linkages within the urban system of the region with some discussion of emerging urban nodes. Part B looks at the specific case studies of the region including the Bohai Sea region, the Japan Sea and case studies of Sapporo, the Japan Sea and case studies of Sapporo, Pusan and Shandong province cities. Part C summarizes this preceding analysis and that the development of regionalism and servicing urban nodes is move likely to emerge from a myriad of linkages developed between the region's cities than from a supra-regional role of nation states. This finding has important implications for regional policy formation suggesting that there should be considerate national support for international linkages between cities.en cities.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.305-305
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• 2010

It is known that a pulse of electrons of high kinetic energy (1-3 eV) in metals can be generated with the deposition of external energy to the surface such as in the absorption of light or in exothermic chemical processes. These energetic electrons are not in thermal equilibrium with the metal atoms and are called "hot electrons" The concept of photon energy conversion to hot electron flow was suggested by Eric McFarland and Tang who directly measured the photocurrent on gold thin film of metal-semiconductor ($TiO_2$) Schottky diodes [1]. In order to utilize this scheme, we have fabricated metal-semiconductor Schottky diodes that are made of Pt or Au as a metallic layer, Si or $TiO_2$ as a semiconducting substrate. The Pt/$TiO_2$ and Pt/Si Schottky diodes are made by PECVD (Plasma Enhanced Chemical Vapor Deposition) for $SiO_2$, magnetron sputtering process for $TiO_2$, e-beam evaporation for metallic layers. Metal shadow mask is made for device alignment in device fabrication process. We measured photocurrent on Pt/n-Si diodes under AM1.5G. The incident photon to current conversion efficiency (IPCE) at different wavelengths was measured on the diodes. We also show that the steady-state flow of hot electrons generated from photon absorption can be directly probed with $Pt/TiO_2$ Schottky diodes [2]. We will discuss possible approaches to improve the efficiency of photon energy conversion.

• Archives of Pharmacal Research
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• v.22 no.1
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• pp.48-54
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• 1999

These studies were designed to examine the differential effect of nitric oxide (NO) and cGMP on glutamate neurotransmission. In primary cultures of rat cerebellar granule cells, the glutamate receptor agonist N-methyl-D-aspartate (NMDA) stimulates the elevation of intracellular calcium concentration ($[Ca^{2+}]_i$), the release of glutamate, the synthesis of NO and an increase of cGMP. Although NO has been shown to stimulate guanylyl cyclase, it is unclear yet whether NO alters the NMDA-induced glutamate release and ${[Ca^{2+}]}_i$ elevation. We showed that the NO synthase inhibitor, NG-monomethyl-L-arginine (NMMA), partially prevented the NMDA-induced release of glutamate and elevation of ${[Ca^{2+}]}_i$ and completely blocked the elevation of cGMP. These effects of NO on glutamate release and [Ca2+]i elevation were unlikely to be secondary to cGMP as the cGMP analogue, dibutyryl cGMP (dBcGMP), did not suppress the effects of NMDA. Rather, dBcGMP slightly augmented the NMDA-induced elevation of ${[Ca^{2+}]}_i$ with no change in the basal level of glutamate or ${[Ca^{2+}]}_i$. The extracellular NO scavenger hydroxocobalamine prevented the NMDA-induced release of glutamate providing indirect evidence that the effect of NO may act on the NMDA receptor. These results suggest that low concentration of NO has a role in maintaining the NMDA receptor activation in a cGMP-independent manner.