• Korea journal of population studies
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• v.13 no.2
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• pp.1-18
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• 1990

This is a study which attempt to analyze changing patierns of economic active popu-lation, t o estimato- future patterns, and exa- mine vartons problems arises by changing c ire u mst ances of t he labor force market in- clunging soici al, economic ic, heathl th and demoi-graph ic aspects. We have constructed series of wotking life table which are useful in syt uiolyioig the lirocess of growth and structural change of labor force. Work i ng life tables represent ihie life eyele of econrmic' activity in hi ypothetical cohorts, that is. gen-erat i on of men Sn bject at eat' b period ot f their lives th given ra to's o mor tali it y and of par-- tici pation in economic activities. The tabloes prot' ide measorues of the alvet'age he ng t able of economically aeti \- e life. and agespecific rates of en trannee' into and retirement from the hahn' force. In const routing working life tables, age-specific activity rates and life tabole popula- titoto which represents contemporary condi-tions of moortality in Korea au'e the basic' maltoerials. We have derived the age-specific rates foorm economically active population survey, whoich were conducted by the Bureau of Statistics, Economic Planning Borard of the Korean government. Working life tables are constructed for men wtable these materi- als in the year of 1970, 1980 and 1988 by a modified Wolfbein-Wool's method. Some of the findings may be summerized as follow : 1) A central part of constructing working life table is calculation of stationary' economic active population, which represents the number of men in the stationtary population extoected to be in the labor force at each age group in the life span. The stationary economic active population by age have generally a universal pattern, where they rise sharply in the early twenties, approach its' peak in the thirties decline thereafter. at first graolually and then more rapidly at an advanced age. Korean men show the same general pa ttern of age distribution of stationary eco-- nomic active population with sharp increase hegining from the age interval of 20 to 24, reaching to maximum level at older age. The population. however, presumably, increased substantially due to increaseing school atte endance rates. Another difference exiSts in the youngest age groups, that is the activity rate in the year of 1988 is lower than that of Japan. The table shows an analysis of changes in the age distrihution of labor force between 1970, 1980 and 1988. 2) It was shown an analysis of changes in the age distribution and cause of separation from labor force. The entrance rate to labor force has increased from 18~\5 persons to 299 persons per 1000 head of stationary population between that of 1980 than that of 1988 for Korean men in 20~24 age group. The entrace rate to labor force shows a rapid entrance appearance concentrated on the 15~24 age group. The separation rate from labor force by retirment in Korea in the year of 1988 shows a great difference of the about four times as much as that of Japan. 3) The functions of table illustrate the patterns of working life of males in Korea in 1970, 1980 and 1988. The average remaining number of economically active years, e at age 15 in 1988 is 46.39 which is 2.12 years of increase compared with that of at age 15 in 1970,1980 and 1988 are 43.90,44.27 and 46.39 respectively, showing steadily increase dur- ing the past double decade the increase in the length of economically active life various age may be considered to have come both from extention of general life expectancy and from increasing entrance rate to economic activity in high age that of working is far greater in 1988 than that of 1980. The gaps between expectation of life and average remaining years of economically active widened due to rapid improvement of mortality level in Ko- rea. This observation together with the population pressure by the appearance of a group of younger population implies that constant increase of economically inactive population among older age group.

• Journal of the Korean Geophysical Society
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• v.2 no.1
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• pp.39-44
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• 1999

High-resolution images are drawn from existing seismic data which were originally obtained by Korea Ocean Research & Development Institute (KORDI) during 1994-1997 for deep seismic studies on the East Sea of Korea. These images are analyzed for mapping Quaternary faults and near-bottom gas pockets. First 12 channels are selected from shot gathers for reprocessing. The processing sequence adopted for high-resolution seismic images comprises data copy, trace editing, true amplitude recovery, common-midpoint sorting, initial muting, prestack deconvolution, bandpass filtering, stacking, highpass filtering, poststack deconvolution, f-x migration, and automatic gain control (AGC). Among these processing steps, predictive deconvolution, highpass filtering, and short window AGC are the most significant in enhancement of resolution. More than 200 Quaternanry faults are interpreted on the migrated sections in the shallow depths beneath the seafloor. Although numerous faults are found mostly at the western continental slope and boundaries of the Ulleung Basin, significant amount of the faults are also indicated within the basin. Many of these faults are believed to be formed with reactivation of basement, from geotectonic activities including volcanism, and often originated in Tertiary, indicating that the tectonic regime of the East Sea might be unstable. Existence of shallow gas pockets casts real hazardous warnings to deep-sea drillings and/or to underwater constructions such as inter-island cables and gas pipelines. On the other hand, discovery of these gas pockets heightens the interests in developing natural resources in the East Sea. Reprocessed seismic sections, however, show no typical seismic characteristics for gas hydrates such as bottom-simulating reflectors in the western continental slope and ocean floor.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.5
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• pp.1-13
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• 2007

In this research, we found out that bridging nodes have great effect on the robustness of protein-protein interaction networks. Until now, many researchers have focused on node's degree as node's essentiality. Hub nodes in the scale-free network are very essential in the network robustness. Some researchers have tried to relate node's essentiality with node's betweenness centrality. These approaches with betweenness centrality are reasonable but there is a positive relation between node's degree and betweenness centrality value. So, there are no differences between two approaches. We first define a bridging node as the node with low connectivity and high betweenness value, we then verify that such a bridging node is a primary factor in the network robustness. For a biological network database from Internet, we demonstrate that the removal of bridging nodes defragment an entire network severally and the importance of the bridging nodes in the network robustness.

• Journal of Environmental Policy
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• v.7 no.4
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• pp.105-134
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• 2008

Local opposition and protest constitute single greatest hurdle to the siting of locally unwanted land uses(LULUs), especially siting of high-level radioactive disposal not only throughout Korea but also throughout the industrialized world. It can be attributed mainly to the NIMBYism, equity problem, and lack of participation. These problems are arisen from rational planning process which emphasizes instrumental rationality. But planning is a value-laden political activity, in which substantive rationality is central. To achieve this goals, we need a sound planning process for siting LULUs, which should improve the ability of citizens to influence the decisions that affects them. By a sound planning process, we mean one that is open to citizen input and contains accurate and complete information. In other word, the public is also part of the goal setting process and, as the information and analyses developed by the planners are evaluated by the public, strategies for solutions can be developed through consensus-building. This method is called as a co-operative siting process, and must be structured in order to arrive at publicly acceptable decisions. The followings are decided by consensus-building method. 1. Negotiation will be held? 2. What is the benefits and risks of negotiation? 3. What are solutions when collisions between national interests and local ones come into? 4. What are the agendas? 5. What is the community' role in site selection? 6. Are there incentives to negotiation. 7. Who are the parties to the negotiation? 8. Who will represent the community? 9. What groundwork of negotiation is set up? 10. How do we assure that the community access to information and expert? 11. What happens if negotiation is failed? 12. Is it necessary to trust each other in negotiations? 13. Is a mediator needed in negotiations?

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.241-248
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• 2014

This study was carried out to evaluate the effects of embryonic stage, cryoprotectant, and freezing-thawing method on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology (ART). Two to eight cell embryos were obtained from oviducts of mated $F_1$ hybrid female mice superovulated by PMSG and hCG. Two-step EG, DMSO and 4-step EG, DMSO were used as cryoprotectant and dehydration and rehydration method of embryos, and slow-cooling or rapid-cooling method was used as frozen program. The survival rates of embryos were measured after thawing and rehydration, and the developmental rates of embryos were compared and observed during culturing embryos for 24, 48, 72, 96 hrs. As for the survival and development rates of embryos according to embryonic stage, the survival rate of 2 cell stage in EG and DMSO was significantly higher than 4~8 cell (65.4% versus 61.2%, 81.1% versus 72.5%) (p<0.01, p<0.01), but the development rates of 4~8 cell embryos in EG and DMSO were significantly higher than 2 cell embryos for whole culture period (p<0.01) and the development rates of 4~8 cell embryos in EG were significantly higher than 2 cell embryos in DMSO (p<0.01). As for the survival and development rates of embryos according to cryoprotectant, the survival rate of 2 cell embryo in DMSO was significantly higher than that in EG(77.0% versus 64.4%) (p<0.01), whereas the development rate of embryos was not differ till 24 hrs. The development rate from morular to hatching blastocyst, however, was sinificantly higher in EG than in DMSO during 48 hr (p<0.01). The survival rate of 4~8 cell embryo was 62.5% in EG and 73.3% in DMSO. The development rates of embryo in EG were significantly higher for whole culture periods (p<0.01, 0.05). In respect to the effect of freezing and thawing program on the survival and development rates of embryos, method of slow cooling and rapid thawing was more effective than that of rapid cooling and rapid thawing. The survival rate of embryo in 2 cell stage was higher than in 4~8 cell stage, and EG appears more effective cryoprotectant than DMSO because EG showed better development rates of embryos in 2 and 4~8 cell stage. Moreover, slow cooling and rapid thawing method was considered as the best cryopreservation program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.113-119
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• 1989

In 1988 the tolerance of corn, sorghum, sorghum-sudangrass. and pearl millet hybrids to simazine and alachlor was tested in field during the growing season and pots during the summer and fall. In field and summer pot experiments(Exp.) the above mentioned four crops were tested at the ratios of simazine WP (50% ai, g/10a) ; alachlor EC (43.7% ai. ml/10a) of 130: 0, 100: 0, 70: 200, 0: 300 and 0: 400 and a sorghum hybrid was tested at 0, 50, 100, 200, 300, and 400ml/10a of alachlor and 70g/10a of simazine+ 200ml/10a of alachlor in fall pot Exp. In corn emergence rate, percent stand, plant height of seedlings, and dry matter(DM) yield were not affected by simazine and alachlor in all Exps. In sorghum and sorghum-sudangrass early growth and DM yield were not affected by simazine and alachlor in field Exp. In contrast, simazine reduced height and dry weight of seedlings slightly without any deterimental effects on emergence and survival rates. but alachlor reduced survival rate, plant height, and dry weight of seedlings significantly in summer pot Exp. In fall Exp. alachlor did not affect emergence rate of a sorghum hybrid, but survival rate, plant height, and dry weight of seedlings reduced with increased levels of alachlor when applied higher than 100ml/10a. In pearl millet simazine did not affect emergence rate, plant height, and DM yield in field, but reduced survival rate, plant height, and dry weight of seedlings in summer pot Exp. However, alachlor reduced DM yield significantly due to a lower percent stand even in the field. In summer pot Exp. although emeregence rate was slightly reduced, all seedlings were dead after emergence. Simazine did not control grasses such as Digitaria sanguinalis, Setaria viridis, Echinochloa crusgalli effectively, but controlled broadleaf weeds. Alachlor controlled all grasses, Porluraca oleracea, and Amaranthus mangostanus, but did not control Acalypha australis and Chenopodium album. A combination of simazine and alachlor controlled weeds more effectively than either simazine or alachlor alone.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.753-762
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• 2004

its digests on the performance of broiler chicks and taurine content in broiler meat. A total of 100 broiler chickens were assigned to five dietary treatments; Control, PM diet(FM), NaOH treated FM diet(NaOH-FM), HN03 treated FM diet(HN03 - FM) and 0.5% synthetic taurine supplemented diet(Taurine). Treated diets were supplemented with FM or FM digests at the level of 5% to the control diet Treated diets were fed during the last 3wks of 6wks feeding. During the finisher period, weight gain of chicks fed FM treatments tended to decrease in general. Feed intakes of FM and Taurine were significantly lower than the control but were not significantly different from NaOH - FM or HN03- PM. Feed conversion rate(feed intake/gain) of NaOH-FM was significantly higher than those of FM and HNOJ - FM but not different from those of the control and Taurine. Taurine content of the control was highest in heart muscle(1482 J1.g/g) followed by leg muscle(778f.lg/g) and breast muscle(79 J1.g/g). Taurine contents of leg and breast muscle were significantly(P< 0.01) affected by treatments but that of heart muscle was not. Taurine content of Taurine treatments was highest in both leg and breast muscle. Taurine content of leg muscle was increased 170"10 by Taurine supplementation, 123% by FM supplementation, 122% by NaOH - FM supplementation and 63% by HNOJ- FM supplementation compared with control. Taurine content of breast muscle of Taurine treatment was 246% higher than the control, but other treatments were not different from the control. In conclusion, supplementation of feather meal at 5% level of broiler diet can enrich taurine content of leg muscle. Chemical treatments of FM were not effective in improving taurine enrichment of broiler meat.

• Journal of Intelligence and Information Systems
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• v.26 no.2
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• pp.43-56
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• 2020

Recommender systems help users make the best choice among various options. Especially, recommender systems play important roles in internet sites as digital information is generated innumerable every second. Many studies on recommender systems have focused on an accurate recommendation. However, there are some problems to overcome in order for the recommendation system to be commercially successful. First, there is a lack of transparency in the recommender system. That is, users cannot know why products are recommended. Second, the recommender system cannot immediately reflect changes in user preferences. That is, although the preference of the user's product changes over time, the recommender system must rebuild the model to reflect the user's preference. Therefore, in this study, we proposed a recommendation methodology using topic modeling and sequential association rule mining to solve these problems from review data. Product reviews provide useful information for recommendations because product reviews include not only rating of the product but also various contents such as user experiences and emotional state. So, reviews imply user preference for the product. So, topic modeling is useful for explaining why items are recommended to users. In addition, sequential association rule mining is useful for identifying changes in user preferences. The proposed methodology is largely divided into two phases. The first phase is to create user profile based on topic modeling. After extracting topics from user reviews on products, user profile on topics is created. The second phase is to recommend products using sequential rules that appear in buying behaviors of users as time passes. The buying behaviors are derived from a change in the topic of each user. A collaborative filtering-based recommendation system was developed as a benchmark system, and we compared the performance of the proposed methodology with that of the collaborative filtering-based recommendation system using Amazon's review dataset. As evaluation metrics, accuracy, recall, precision, and F1 were used. For topic modeling, collapsed Gibbs sampling was conducted. And we extracted 15 topics. Looking at the main topics, topic 1, top 3, topic 4, topic 7, topic 9, topic 13, topic 14 are related to "comedy shows", "high-teen drama series", "crime investigation drama", "horror theme", "British drama", "medical drama", "science fiction drama", respectively. As a result of comparative analysis, the proposed methodology outperformed the collaborative filtering-based recommendation system. From the results, we found that the time just prior to the recommendation was very important for inferring changes in user preference. Therefore, the proposed methodology not only can secure the transparency of the recommender system but also can reflect the user's preferences that change over time. However, the proposed methodology has some limitations. The proposed methodology cannot recommend product elaborately if the number of products included in the topic is large. In addition, the number of sequential patterns is small because the number of topics is too small. Therefore, future research needs to consider these limitations.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.634-640
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• 2007

Our previous study suggested that n-3 fatty acid deficiency was associated with significantly reduced spatial learning as assessed by Morris water maze test. Here we investigated an effect of n-3 fatty acid deficiency on rat brain, retina and serum fatty acyl compositions at 15 wks age using a first generational artificial rearing technique. Newborn Rat pups were separated on day 2 and assigned to two artificial rearing groups or a dam-reared control group. Pups were hand fed artificial milk via custom-designed nursing bottles containing either 0.02%(n-3 Deficient) or 3.1% (n-3 Adequate) of total fatty acids as a-linolenic acid(LNA). At day 21, rats were weaned to either n-3 deficient or n-3 adequate pelleted diets and fatty acid compositions of brain, retina and liver were analyzed at 15 wks age. Brain docosahexaenoic acid(DHA) was lower(58% and 61%, P<0.05) in n-3 deficient in comparison to n-3 adequate and dam-reared groups, receptively, while brain docosapentaenoic acid(DPAn-6) was increased in the n-3 deficient group. In retina and serum fatty acid compositions, the decreased precentage of DHA and increased precentage of DPAn-6 were observed. These results suggested that artificial rearing method can be used to produce n-3 fatty acid deficiency in the first generation and that adequate brain DHA levels are required for optimal brain function.

• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.368-380
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• 1999

Purpose: The purpose of this study was to evaluate and compare the scintigraphic findings and diagnostic accuracy of double-phase Tc-99m sestamibi scan in primary and secondary hyperparathyroidism (HPT). Materials and Methods: We retrospectively reviewed 16 cases of primary (18 lesions) and 11 cases of secondary HPT (44 lesions) who underwent Tc-99m-sestamibi scan before the surgical intervention. Scan was performed using LEM camera (Siemens, Germany) after the injection of 740MBq of Tc-99m sestamibi. Routine image consisted of baseline and 3-hour delayed images and each image was obtained using both parallel and pine hole collimator. The study population was 27 patients (male/female=5/22, age: $49.1{\pm}10.8$). Results: Eighteen lesions of primary HPT consisted of 13 adenomas and S hyperplasias, while all lesions of secondary HPT were hyperplasias. Among the case of primary HPT, we could detect all the lesions of 13 adenomas but only 2 lesions of 5 hyperplasias (40%) could be detected by double phase scintigraphy. Three cases of primary lesion showed decreased uptake in delayed images compared with baseline. The sensitivity, specificity, positive predictive value and accuracy of primary and secondary HPT were 58.8% (10/17), 83.3% (10/12), 83.3% (10/12), 75.9% (22/29), and 37.5% (15/40), 50% (2/4), 88.2% (15/17), 38.6% (17/44), respectively. Overall sensitivity, specificity, positive predictive value and accuracy were 43.9% (25/57), 75% (12/16), 86.2% (25/29), and 53.4% (39/73). There were no statistical difference between the weight of primary and secondary HPT lesion (p>0.05). Conclusion: Tc-99m sestamibi scan is fairly good modality to detect parathyroid lesion in patient with primary HPT before the surgical intervention. However, since some of cases may reveal decreased uptake in delayed image, a careful attention to the findings of baseline images may be helpful. Still the low accuracy of sestamibi scan in diagnosis of secondary HPT prohibits routine use of it for this disease.