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Structural Behavior of Mixed $LiMn_2O_4-LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ Cathode in Li-ion Cells during Electrochemical Cycling

  • Yun, Won-Seop;Lee, Sang-U
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.5-5
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    • 2011
  • The research and development of hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV) and electric vehicle (EV) are intensified due to the energy crisis and environmental concerns. In order to meet the challenging requirements of powering HEV, PHEV and EV, the current lithium battery technology needs to be significantly improved in terms of the cost, safety, power and energy density, as well as the calendar and cycle life. One new technology being developed is the utilization of composite cathode by mixing two different types of insertion compounds [e.g., spinel $LiMn_2O_4$ and layered $LiMO_2$ (M=Ni, Co, and Mn)]. Recently, some studies on mixing two different types of cathode materials to make a composite cathode have been reported, which were aimed at reducing cost and improving self-discharge. Numata et al. reported that when stored in a sealed can together with electrolyte at $80^{\circ}C$ for 10 days, the concentrations of both HF and $Mn^{2+}$ were lower in the can containing $LiMn_2O_4$ blended with $LiNi_{0.8}Co_{0.2}O_2$ than that containing $LiMn_2O_4$ only. That reports clearly showed that this blending technique can prevent the decline in capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and related structural phase transitions for these composite cathodes. In this presentation, we will report our in situ x-ray diffraction studies on this mixed composite cathode material during charge-discharge cycling. The mixed cathodes were incorporated into in situ XRD cells with a Li foil anode, a Celgard separator, and a 1M $LiPF_6$ electrolyte in a 1 : 1 EC : DMC solvent (LP 30 from EM Industries, Inc.). For in situ XRD cell, Mylar windows were used as has been described in detail elsewhere. All of these in situ XRD spectra were collected on beam line X18A at National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory using two different detectors. One is a conventional scintillation detector with data collection at 0.02 degree in two theta angle for each step. The other is a wide angle position sensitive detector (PSD). The wavelengths used were 1.1950 ${\AA}$ for the scintillation detector and 0.9999 A for the PSD. The newly installed PSD at beam line X18A of NSLS can collect XRD patterns as short as a few minutes covering $90^{\circ}$ of two theta angles simultaneously with good signal to noise ratio. It significantly reduced the data collection time for each scan, giving us a great advantage in studying the phase transition in real time. The two theta angles of all the XRD spectra presented in this paper have been recalculated and converted to corresponding angles for ${\lambda}=1.54\;{\AA}$, which is the wavelength of conventional x-ray tube source with Cu-$k{\alpha}$ radiation, for easy comparison with data in other literatures. The structural changes of the composite cathode made by mixing spinel $LiMn_2O_4$ and layered $Li-Ni_{1/3}Co_{1/3}Mn_{1/3}O_2$ in 1 : 1 wt% in both Li-half and Li-ion cells during charge/discharge are studied by in situ XRD. During the first charge up to ~5.2 V vs. $Li/Li^+$, the in situ XRD spectra for the composite cathode in the Li-half cell track the structural changes of each component. At the early stage of charge, the lithium extraction takes place in the $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component only. When the cell voltage reaches at ~4.0 V vs. $Li/Li^+$, lithium extraction from the spinel $LiMn_2O_4$ component starts and becomes the major contributor for the cell capacity due to the higher rate capability of $LiMn_2O_4$. When the voltage passed 4.3 V, the major structural changes are from the $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component, while the $LiMn_2O_4$ component is almost unchanged. In the Li-ion cell using a MCMB anode and a composite cathode cycled between 2.5 V and 4.2 V, the structural changes are dominated by the spinel $LiMn_2O_4$ component, with much less changes in the layered $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component, comparing with the Li-half cell results. These results give us valuable information about the structural changes relating to the contributions of each individual component to the cell capacity at certain charge/discharge state, which are helpful in designing and optimizing the composite cathode using spinel- and layered-type materials for Li-ion battery research. More detailed discussion will be presented at the meeting.

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Geochemical and Isotopic Study of the Onjeongri Granite in the Northern Gyeongsang Basin, Korea : Comparison with Cretaceous to Tertiary Granitic Rocks in the Other Part of the Gyeongsang Basin and the Inner Zone of Southwest Japan (경상분지 북부에 분포하는 온정리 화강암에 대한 암석화학적, 동위원소 지구화학적 연구 : 경상분지 다른 지역과 서남 일본 내대에 분포하는 백악기-제 3기 화강암류와의 비교 고찰)

  • 정창식;권성택;김정민;장병욱
    • The Journal of the Petrological Society of Korea
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    • v.7 no.2
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    • pp.77-97
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    • 1998
  • We analyzed geochemical and radiogenic isotope data to investigate the genesis and source characteristics of the Onjeongri granite in the northern part of the Gyeongsang Basin. Field observation and K-Ar ages confirm late Cretaceous intrusion (ca. 87 Ma) of the Onjeongri granite. The hornblende geobarometery gives less than 2 kbar for the emplacement pressure of the Onjeongri granite. Geochemical and isotopic compositions suggest that the Onjeongri granite was formed in a relatively immature arc system. $SiO_2$ contents show a negative linear relationship with initial $^{87}Sr/^{86}Sr$ ratios, and an apparent positive correlation with $^{207}Pb/^{204}Pb$ ratios, suggesting an incomplete mixing or assimilation. However, the isotopic data known for any exposed rocks of the study area do not fit as an endmember, implying that the contaminant might reside in the lower crust. A review of published isotopic ages, geochemical, and Sr and Nd isotopic data for the Cretaceous to Tertiary granites in the Gyeongsang Basin indicates the followings. 1) Granitic magmatism in the Gyeongsang Basin were episodic. 2) Granitic rocks in the basin were derived from young (< 0.9 Ga) lower crust, and their isotopic signatures reflect heterogeneous source region. Geochemical and isotopic signatures of granitic rocks in the basin are difficult to explain by upper crustal contamination. 3) Granites in the Gyeongsang Basin have closely related to those in the San in Belt of the Inner Zone of Southwest Japan in terms of age, petrography, and isotopic and geochemical composition. 4) Sr-Nd isotopic signatures of the Onjeongri granite are relatively primitive compared with granitic rocks in the other parts of the Gyeongsang Basin and in the Inner Zone of Southwest Japan.

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Composition of Amino Acids, Minerals, and Heavy Metals in Differently Cooked Laver (Porphyra tenera) (김(Porphyra tenera)의 조리방법에 따른 아미노산, 무기질, 중금속 함량 분석)

  • Hwang, Eun-Sun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.8
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    • pp.1270-1276
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    • 2013
  • Laver, a red algae belonging to the genus Porphyra tenera, is one of the most widely consumed edible seaweeds in Korea, China, and Japan. Lavers are usually consumed in dried, roasted, and seasoned forms to improve their palatability. We evaluated the composition of amino acids, minerals, and trace heavy metals in these three differently cooked forms of laver. The moisture and ash contents of three differently cooked lavers ranged from 1.49~9.69% and 6.07~10.31%, respectively. The crude protein and lipid content ranged from 17.24~36.88% and 0.52~42.42%, respectively. Dried laver was found to be a good source of amino acids such as taurine, alanine, and glutamic acid (871.10 mg, 833.53 mg, and 719.77 mg per 100 g dry weight, respectively). Laver was a good source of macro and micro minerals such as K, Ca, Mg, Na, P, I, and Fe, although laver more extensively cooked (roasted and seasoned) contained less minerals compared to the dried form. Mercury levels in the three differently cooked forms of laver were all less than 100 ng/g dry weight (the limit of detection with our methodology). The levels of arsenic were the most abundant elements in the differently cooked laver. There was a clear variation, depending on the cooking process, in terms of amino acid, mineral, and trace metal contents of laver.

A Study on the Fashion Information Activities of Clothing Manufactures (의류제조업체의 패션 정보활동에 관한 연구)

  • 송미령
    • Journal of the Korean Society of Costume
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    • v.22
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    • pp.135-158
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    • 1994
  • The fashion industry of today is closely re-lated with the information activity. This study investigates now they take advantage of the fashion information by analysing some related fields including fashion design. Furthormore this study identify the factor which makes the design activity distinctive and predict and fu-ture trend in design. The purposes of this study through analysis are : to help find the way to facilitate the fashion industry and to develop the fashion merchandising in order to activate the re-cession of manufacturers and to improve competitiveness in the world market and to contribute to the academic achievement in the study of fashion merchandising. In the experimental approach the tasks of research are as follows: Research 1: The application of fashion infor-mation is discussed in terms of process and level. Research 2: The differences of the fashion design activities are captured on the basis of the characteristics of manufactures and fashion specialists and fashion information ac-tivities. The factors are identified which pre-dict and discriminate the results of fashion de-sign activities. The questionaire and interview were conduc-ted among women's clothing manufactures in Seoul and their fashion specialists in charge of merchandise development. The methods of survey were designed on the basis of theories developed so far and on he advice from the social scientists and fashion specialists. the methods were corrected and complemented through the 1st and 2nd preliminary investigations before their application For data analysis cronbach's a coefficient fre-quency percentage average standard devi-ation pearson's correlation coefficient were calculated and t-test F-test(ANOVA) Duncan's multiple range test regression and Discriminant analysis were conducted. The results of analysis throughout the experimen-tal studies were as follows: 1. The analysis of fashion in formation (1) the present application of information a. The source of information : Both the foreign and the domestic information came mostly from fashion journals magazines newspapers and other periodicals, the main source of market information was collected from the survey of popular items in recent years the data about the life-style of customers and their tastes for wearing were widely used as the information about consumers. b. The applicaton of information : The most widely used information was about fabrics. The foreign information was prefered on the whole. The domestic problems pointed out in this investgation were that the domestic journals showed the lack of specialty and the special organizations for fashion informatino were in urgent need. (2) The research of fashion information a. The various processes and levels of in-formation activities: Among the process of collection analysis and distribution the collec-tion process showed a good acheivement whereas the distribution whereas the distribution didn't. In levels of the systematic activities the acceptance of support and the utility of supported instruments the first indicated a high degree whereas the second showed lowest. b. The correlationship among subvariables : There was a significant correlation between the collection and the analysis process. The systematic activities revealed close relation-ship with the analysis process and the accept-ance of support with the distribution process. The close correlation was found between the utility of supported instruments and the analy-sis process. 2. The analysis of the fashion design activities (1) No significant differences were found in the design activities when the characteristics of companies were compared only. (2) According to the characteristics of fashion specialists the one with age experi-ence and high income showed rather good achievement but no significant differences were captured among sex department in charge title academic background education in abroad and field experience (3) The fashion information activities were strongly correlated with the design achieve-ment : The analysis process and the system-atic activity level had a great influence on the design activities. (4) In order to examine which cha-racteristics in (1-3) made it possible to pre-dct and discriminate the achievement in de-sign activities the Discriminant analysis was carried out. The results were as follows: the fashion information activities showed the highest discriminant rate. Next came the in-come level experience and age in that order Those four variables discrimated 37 from 50 who showed great achievement in design area (74%) and 51 from 83 in low achievement group (81%) Thus the total discriminant rate was 77.5%.

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Optimal Application Rate of Mixed Expeller Cake and Rice Straw and Impacts on Physical Properties of Soil in Organic Cultivation of Tomato (토마토 유기재배에서 혼합유박과 볏짚의 적정시용량 및 토양 물리성에 미치는 영향)

  • Lim, Tae-Jun;Park, Jin-Myeon;Lee, Seong-Eun;Jung, Hyun-Cheol;Jeon, Sang-Ho;Hong, Soon-Dal
    • Korean Journal of Environmental Agriculture
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    • v.30 no.2
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    • pp.105-110
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    • 2011
  • BACKGROUND: In this study, 5 different treatments such as non-treatment, mixed expeller cake 1.0 N (standard nitrogen fertilizer), rice straw, rice straw+mixed expeller cake 0.5 N, rice straw+mixed expeller cake 1.0 N were performed over 4 cropping seasons over 2 years in order to identify the optimal application rate of mixture of rice straw and mixed expeller cake, organic source in organic cultivation of tomatoes. METHODS AND RESULTS: There was no difference in all treatments in case of 200 mg/kg in the nitrate nitrogen content in soil prior to the first cropping season test under the criteria for nitrogen nutrient based on yield of crops, cultivation without fertilizers seems possible. But in the second cropping season, no treatment and rice straw showed the reduction of yield and in the third cropping season, rice-straw+mixed expeller cake 0.5 N treatment showed the significant difference. The content of nitrate nitrogen in soil prior to cropping seasons was evaluated in 160 mg/kg and standard fertilization such as mixed expeller cake, source of nitrogen, are needed due to the deficiency of nitrogen. In terms of application of organic resources, rice straw showed the effects of improvements on physical properties of soil such as bulk density, cation exchange capacity and humus contents, but the mixed expeller cake did not show any significant differences in improvements on physical properties of soil. CONCLUSION(s): Fertilizer management in organic cultivation of tomatoes is thought to produce the reliable quantity of crops as well as keep the high quality of soils by using the optimal application rate of mixed expeller cake according to the contents of nitrate nitrogen in soil and rice straw which improves the physical properties of soil.

A Basic Study on the Establishment of Evaluation Items for the Resiliency of Planting Landscape in Hahoe and Yangdong of World Cultural Heritage (세계문화유산 하회와 양동의 식생경관 진정성 유지를 위한 평가항목 설정 기초 연구)

  • Lee, Chang-Hun;Shin, Hyun-Sil
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.2
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    • pp.21-29
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    • 2018
  • This study was wanted to select a value evaluation item to maintain the authenticity of the Planting Landscape in Hahoe and Yangdong villages. Above all, after checking the suitability of the 43 selected items by the Focus Group Interview, the weight was calculated in the Analytic Hierarchy Process expert questionnaire to establish the importance of the indicators for the development of the assessment items. The expert analysis analyzed the importance of 2 sections, 6 divisions and 11 detailed categories, and summarized the results of the study as follows : First, the comparative importance of each category and selection of the assessment items for the stabilization of the Planting Landscape of Hahoe and Yangdong indicated that cultural values are more important than biological values. In particular, details of the biological values of trees were derived with relatively low estimates, except for the specific characteristics of species and items of type of tree. Second, as a result of verification of the suitability of the 43 items selected by the Focus Group Interview, the source diameter, the collection width, reception, flushing, supersonality, records, memorials, 11 items were selected, Third, the results of the importance evaluation of the value properties for maintaining the resistance of vegetation through the Analytic Hierarchy Process were : specific in biological values (0.187), steady (0.094), and water pipe width (2007). There was relatively little difference in the highest weights, the width of the pipe except for the lowest value received, and the source diameter flushing. Fourth, the results of an evaluation of the importance of a value property aimed at historical values were whether or not the cultural asset was designated (0.134), the record value (0.092), the time (0.088), and the monument (0.063). In terms of the importance of evaluating the historical values of Planting sites consisting of Hahoe and Yangdong, the importance of designation of cultural properties was considered to be relative to the maintenance of the Planting Landscape including culture and history. Based on the assessment items and weighted values of the Planting Landscape of Yangdong Village and the World Cultural Heritage below and below, this study's Analytic Hierarchy Process can be applied to actual criteria for the assessment of the authenticity of trees in the village. Based on the assessment items and weighted values of the Planting Landscape in Hahoe and Yangdong villages, a follow-up study on the assessment standards for the authenticity of trees in the village will be left as a future task.

A Study on the Cubism - In it's relation to Bergsonian Philosophy and Simultaneity - (큐비즘에 관한 연구 - 베르그송 철학과 동시성 개념을 중심으로 -)

  • Ryu, Ji-Seok;Oh, Chan-Ohk
    • Archives of design research
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    • v.18 no.3 s.61
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    • pp.117-128
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    • 2005
  • The French Belle Epoque is a period where the literary and artistic movement was very activated. The birth of the cubism reflects this atmosphere of the times and the change of paradigm in all fields. The Bergsonism is often designated as one of the important backgrounds of cubism. The problem consists in knowing if Bergsonian ideas gave real influence on the cubist movement and up to what point. Our analysis will show that it is not homogenous and very variable according to painters. In the case of Picasso and Braques it seems be a simple inspiration of Zeitgeist. But the influence upon Metzinger and Gleizes is explicit. The text of 1912, Du cubism, prove their attachment to his thought. The key concept of cubist theory, influenced by Bergsonian philosophy, is the concept of simultaneity. Cubist simultaneity is in one hand a reflection of an artist's psychological experience and the other hand a synthesis of multiple views for grasping the object in itself by the way of conceptual representation. The temporal simultaneity could be identified with the notion of memory, which is a temporal continuity connecting the past to dynamic present. The spatial simultaneity is a juxtaposition of multiple views obtained by the movement around the object. But the dose reading of Bergson's text shows that there is a divergence between the notion of cubist simultaneity and his ideas. The biased interpretation is often, as well as the strict understanding, like the history shows us well, a great source of inspiration and creativity. The cubist mouvement is not far from this case.

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Combustion Characteristics of Cow Manure Pellet as a Solid Fuel Source (고체연료원으로서의 우분 펠릿 연소특성)

  • Jeong, Kwang-Hwa;Lee, Dong-jun;Lee, Dong-Hyun;Lee, Sung-Hyoun
    • Journal of the Korea Organic Resources Recycling Association
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    • v.27 no.2
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    • pp.31-40
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    • 2019
  • In Korea, 51,013 thousand tons of livestock manure was generated in 2018. A total of 46,530 thousand tons, which is 91.2% of the total amount of livestock manure generated, was treated by composting(40,647 thousand tons) or liquid fertilization(5,884 thousand tons) method. At present, the policy of livestock manure treatment in Korea is to make livestock manure into organic fertilizer(compost, liquid fertilizer) and then to applicate it on agricultural land. And this policy is very effective in terms of livestock manure treatment and nutrient recycling. However, considering the steadily declining farmland area for decades, the use of livestock manure compost could be limited in the future. There is also concern that local nutrient overloading, nutrient management regulation, and restrictions on the number of livestock may become serious problem for livestock manure treatment. In addition, there are some opinions that nutrient derived from livestock manure may flow into tributaries of major dams. In recent years, there has been a suspicion that fine dust may be generated from livestock manure compost. In recent years, the use of livestock manure fertilizer has been rapidly increasing, there is a growing demand of the development of new technologies for livestock manure treatment. Especially, cow excretes a larger amount of manure than other livestock, so that the efficiency of development of new technology for cow manure treatment will be high. Therefore, in this study, the combustion characteristics of cow manure pellet were investigated in order to analyzed whether cow manure could be used as source of solid fuel. During the combustion test, the weight loss of the cow manure pellet began to increase when the temperature of the combustion chamber reached $300^{\circ}C$. The ratio of $H_2$, $CH_4$, CO in the pyrolysis gas produced in the pyrolysis process of cow manure pellet were 6.65~11.62%, 0.58~1.54 and 11.47~14.07%, respectively.

Analysis of Research Trends of 'Word of Mouth (WoM)' through Main Path and Word Co-occurrence Network (주경로 분석과 연관어 네트워크 분석을 통한 '구전(WoM)' 관련 연구동향 분석)

  • Shin, Hyunbo;Kim, Hea-Jin
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.179-200
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    • 2019
  • Word-of-mouth (WoM) is defined by consumer activities that share information concerning consumption. WoM activities have long been recognized as important in corporate marketing processes and have received much attention, especially in the marketing field. Recently, according to the development of the Internet, the way in which people exchange information in online news and online communities has been expanded, and WoM is diversified in terms of word of mouth, score, rating, and liking. Social media makes online users easy access to information and online WoM is considered a key source of information. Although various studies on WoM have been preceded by this phenomenon, there is no meta-analysis study that comprehensively analyzes them. This study proposed a method to extract major researches by applying text mining techniques and to grasp the main issues of researches in order to find the trend of WoM research using scholarly big data. To this end, a total of 4389 documents were collected by the keyword 'Word-of-mouth' from 1941 to 2018 in Scopus (www.scopus.com), a citation database, and the data were refined through preprocessing such as English morphological analysis, stopwords removal, and noun extraction. To carry out this study, we adopted main path analysis (MPA) and word co-occurrence network analysis. MPA detects key researches and is used to track the development trajectory of academic field, and presents the research trend from a macro perspective. For this, we constructed a citation network based on the collected data. The node means a document and the link means a citation relation in citation network. We then detected the key-route main path by applying SPC (Search Path Count) weights. As a result, the main path composed of 30 documents extracted from a citation network. The main path was able to confirm the change of the academic area which was developing along with the change of the times reflecting the industrial change such as various industrial groups. The results of MPA revealed that WoM research was distinguished by five periods: (1) establishment of aspects and critical elements of WoM, (2) relationship analysis between WoM variables, (3) beginning of researches of online WoM, (4) relationship analysis between WoM and purchase, and (5) broadening of topics. It was found that changes within the industry was reflected in the results such as online development and social media. Very recent studies showed that the topics and approaches related WoM were being diversified to circumstantial changes. However, the results showed that even though WoM was used in diverse fields, the main stream of the researches of WoM from the start to the end, was related to marketing and figuring out the influential factors that proliferate WoM. By applying word co-occurrence network analysis, the research trend is presented from a microscopic point of view. Word co-occurrence network was constructed to analyze the relationship between keywords and social network analysis (SNA) was utilized. We divided the data into three periods to investigate the periodic changes and trends in discussion of WoM. SNA showed that Period 1 (1941~2008) consisted of clusters regarding relationship, source, and consumers. Period 2 (2009~2013) contained clusters of satisfaction, community, social networks, review, and internet. Clusters of period 3 (2014~2018) involved satisfaction, medium, review, and interview. The periodic changes of clusters showed transition from offline to online WoM. Media of WoM have become an important factor in spreading the words. This study conducted a quantitative meta-analysis based on scholarly big data regarding WoM. The main contribution of this study is that it provides a micro perspective on the research trend of WoM as well as the macro perspective. The limitation of this study is that the citation network constructed in this study is a network based on the direct citation relation of the collected documents for MPA.

Legal Issues and Tasks for the Establishment of National Contract for Peace and Unification ('평화통일국민협약' 추진의 법제도적 과제)

  • Choi, Cheol-Young
    • Journal of Legislation Research
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    • no.55
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    • pp.57-94
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    • 2018
  • Crisis of trust in Korean society, especially south-south conflicts among Korean political circle, civil society and peoples on the issue of the Korean peninsula policy driven by south Korean government, have weakened the sustainable and consistent energy of the policy for peace and unification of Korea peninsula. At the moment of drastic change of south-north relation in Korean peninsula, National agreement as a foundation of sustainable peace and unification policy has very important meaning. Because of this, national contract of unification as a kind of social concertation, has been demanded. National contract for peace and unification is an unprecedented process for making unofficial legal norm because it authorize quasi-legislative binding force on the agreement which is concluded by the Korean political circle, civil society and peoples for the peace and unification of Korean peninsula. National contract for peace and unification includes 'agreed aim and principles' for peace, prosperity and unification as well as process and result. And National contract for peace and unification, also is characterized long duration of aim achievement and openness of participating subjects. In terms of law, it will be legitimate source for comprehensive modification of international and internal law. In addition, The nature of National contract for peace and unification, as a people's law, should be considered as soft law which has the power to realize its contents through the enactment of legislation and policy. In order to guarantee the establishment and effectiveness of National contract for peace and unification, the setting of organization is need to determine the range of representatives, who participate in the process of contract making, procedure of contract and to carry out the contract after the conclusion of National contract for peace and unification. For the reason, the Council of National Contract for Peace and Unification as a independent administrative government committee and 'Act on National Contract for Peace and Unification' is needed.