• Journal of Intelligence and Information Systems
• /
• v.22 no.3
• /
• pp.113-127
• /
• 2016

Among the techniques for recommendation, collaborative filtering (CF) is commonly recognized to be the most effective for implementing recommender systems. Until now, CF has been popularly studied and adopted in both academic and real-world applications. The basic idea of CF is to create recommendation results by finding correlations between users of a recommendation system. CF system compares users based on how similar they are, and recommend products to users by using other like-minded people's results of evaluation for each product. Thus, it is very important to compute evaluation similarities among users in CF because the recommendation quality depends on it. Typical CF uses user's explicit numeric ratings of items (i.e. quantitative information) when computing the similarities among users in CF. In other words, user's numeric ratings have been a sole source of user preference information in traditional CF. However, user ratings are unable to fully reflect user's actual preferences from time to time. According to several studies, users may more actively accommodate recommendation of reliable others when purchasing goods. Thus, trust relationship can be regarded as the informative source for identifying user's preference with accuracy. Under this background, we propose a new hybrid recommender system that fuses CF and social network analysis (SNA). The proposed system adopts the recommendation algorithm that additionally reflect the result analyzed by SNA. In detail, our proposed system is based on conventional memory-based CF, but it is designed to use both user's numeric ratings and trust relationship information between users when calculating user similarities. For this, our system creates and uses not only user-item rating matrix, but also user-to-user trust network. As the methods for calculating user similarity between users, we proposed two alternatives - one is algorithm calculating the degree of similarity between users by utilizing in-degree and out-degree centrality, which are the indices representing the central location in the social network. We named these approaches as 'Trust CF - All' and 'Trust CF - Conditional'. The other alternative is the algorithm reflecting a neighbor's score higher when a target user trusts the neighbor directly or indirectly. The direct or indirect trust relationship can be identified by searching trust network of users. In this study, we call this approach 'Trust CF - Search'. To validate the applicability of the proposed system, we used experimental data provided by LibRec that crawled from the entire FilmTrust website. It consists of ratings of movies and trust relationship network indicating who to trust between users. The experimental system was implemented using Microsoft Visual Basic for Applications (VBA) and UCINET 6. To examine the effectiveness of the proposed system, we compared the performance of our proposed method with one of conventional CF system. The performances of recommender system were evaluated by using average MAE (mean absolute error). The analysis results confirmed that in case of applying without conditions the in-degree centrality index of trusted network of users(i.e. Trust CF - All), the accuracy (MAE = 0.565134) was lower than conventional CF (MAE = 0.564966). And, in case of applying the in-degree centrality index only to the users with the out-degree centrality above a certain threshold value(i.e. Trust CF - Conditional), the proposed system improved the accuracy a little (MAE = 0.564909) compared to traditional CF. However, the algorithm searching based on the trusted network of users (i.e. Trust CF - Search) was found to show the best performance (MAE = 0.564846). And the result from paired samples t-test presented that Trust CF - Search outperformed conventional CF with 10% statistical significance level. Our study sheds a light on the application of user's trust relationship network information for facilitating electronic commerce by recommending proper items to users.

• Resources Recycling
• /
• v.28 no.6
• /
• pp.79-86
• /
• 2019

Recently, the use of lithium ion battery(LIB) has increased. As a result, the price of lithium and the amount spent lithium on ion battery has increased. For this reason, research on recycling lithium in waste LIBs has been conducted1). In this study, the effect of roasting for the selective lithium leaching from the spent LIBs is studied. Chemical transformation is required for selective lithium leaching in NCM LiNi_xCo_yMn_zO₂) of the spent LIBs. The carbon in the waste EV cell powder reacts with the oxygen of the oxide at high temperature. After roasting at 550 ~ 850 ℃ in the Air/N₂ atmosphere, the chemical transformation is analysed by XRD. The heat treated powders are leached at a ratio of 1:10 in D.I water for ICP analysis. As a result of XRD analysis, Li₂CO₃ peak is observed at 700 ℃. After the heat treatment at 850 ℃, a peak of Li₂O was confirmed because Li₂CO₃ is decomposed into Li₂O and CO₂ over 723 ℃. The produced Li₂O reacted with Al at high temperature to form LiAlO₂, which does not leach in D.I water, leading to a decrease in lithium leaching ratio. As a result of lithium leaching in water after heat treatment, lithium leaching ratio was the highest after heat treatment at 700 ℃. After the solid-liquid separation, over 45 % of lithium leaching was confirmed by ICP analysis. After evaporation of the leached solution, peak of Li₂CO₃ was detected by XRD.

• The Korean Journal of Pharmacology
• /
• v.25 no.1
• /
• pp.13-21
• /
• 1989

The circadian rhythm of spontaneous motor activity was not significantly altered by $T_4$(4mg/kg, i.p. inj. once a day for 5 days: $T_4$) and PTU (fed ad lib in 0.01% drinking water for 5 weeks: PTU). The plasma thyroxine level was markedly increased by $T_4$ but reduced by PTU, and the plasma thyrotropin level was markedly increased by PTU but moderately increased by $T_4$. Clonidine slightly increased the plasma CS level, but the clonidine effect was significantly enhanced by $T_4-pretreatment$. The brain NE and MHPG contents were little affected by $T_4$ but the NE content was significantly decreased by PTU. The SS-induced increase of plasma CS level was moderately decreased by PTU but increased by $T_4$. However, clonidine significantly inhibited the SS-induced increase, and the inhibitory effect of clonidine was not significantly affected by PTU and $T_4$, respectively. The brain MHPG content and MHPG/NE ratio were significantly decreased by clonidine but increased by SS. The clonidine- and SS-induced changes of brain MHPG content and MHPG/NE ratio were not altered by $T_4$. PTU did not affect the SS-induced increase of brain NE turnover but significantly attenuated the clonidine-induced decrease. The SS-induced increases of brain MHPG content and MHPG/NE rtatio were markedly inhibited by clonidine, and the inhibitory effect of clonidine was not affected by $T_4$ and PTU, respectively. These results suggest that the responses to swim-stress is not signigicantly affected by the alteration of thyroid function and that the hypothalamo-adenohypophysis-adrenocortical stimulation in response to swim-stress seems to be mediated via hypothalamic noradrenergic activation, and the stress response may be inhibited by the agonistic activity of clonidine on the presynaptic ${\alpha}_2-adrenoceptor$.

• Journal of Animal Environmental Science
• /
• v.15 no.1
• /
• pp.9-16
• /
• 2009

This study, tasting 14 months, was conducted to investigate the effects of different pen size and group size on growing-fattening characteristics of Hanwoo steers. Forty-eight, 12-month-old Hanwoo steers($305.8{\pm}32.2\;kg$) were randomly assigned to three groups($35.28\;m^2$; n=4 heads, $70.56\;m^2$; n=8 heads, $105.84\;m^2$; n=12 heads) and reared in separate pens with a constant space allowance of $8.82m^2$ per head from 12 to 21 month of age and then regrouped to 4 heads per pen. A common diet including concentrate(limited) and forage(ad lib) was provided to all the animals. Images of live animal ultrasonic back fat thickness, longissimus muscle area and Marbling score were evaluated in three months interval from 12 months of age using an ultrasound equipment(HS-2000) at the 13th rib and lumber vertebra interface of left side. Significant differences of ADG was found mainly at $15{\sim}18$ month and $18{\sim}21$ month fattening stages(p<0.05). Marbling score(MS) was higher(p<0.05) in 12 heads group when compared with that of 4 and 8 heads groups after 18 months. Animals in 12 heads group had the lowest Average daily gain(ADG) but showed the highest longissimus muscle area(LMA) and marbling score(MS). In addition, Hanwoo steers in 12 heads group obtained a higher quality appearance(HQA) of 82.7% than that of other treatments. The results indicated that Hanwoo steers housed on large group size and pen size decreased their ADG but improved meat quality.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.10
• /
• pp.1271-1278
• /
• 2007

In this study, the ability of Styela clava or Styela plicata to reduce ethanol-induced hepatotoxicity and hepatic and leucocytic DNA damages was evaluated. Twenty four male SD rats were given 25% ethanol containing water (ad lib, p.o.) and divided into 3 groups; ethanol treated control group (EtOH), ethano1+3% S. clava (EtOH+SC), and ethano1+3% S. plicata (EtOH+SP). After 6 weeks, the supplementation of S. clava reduced the plasma ALT, ALP and LDH activities significantly (p<0.05), while S. plicata induced significant decrease in the plasma LDH activity only. The comet assay was employed to quantify the alcohol-induced DNA damage in rat hepatocytes and leucocytes. A significant protective effect on hepatic and leucocytic DNA damages was observed in S. clava or S. plicata supplemented groups compared to the EtOH control group. The hepatic DNA damage was correlated positively with plasma ALP and LDH activities. These results demonstrated that S. clava or S. plicata supplementation protected alcohol-induced hepatic and leucocytic DNA damage.

• Applied Biological Chemistry
• /
• v.32 no.3
• /
• pp.240-248
• /
• 1989

The effects of the soil properties on the contents of catalpol, sugar and ash in the rhizoma of Ji-whang (Rehmannia glutinosa Lib. var. purpurea Makino) were studied to get information on cultivation for higher quality production. Catalpol contents of the rhizoma of Ji-whang ranged from 3.75 to 4.36%. It was shown that the sand contents of soil was positively correlated with the catalpol contents, and negatively correlated with the contents of fructose and galactose in the rhizoma of Ji-whang. The sand contents of subsoil was also negatively correlated with the contents of ash and acid insoluble ash in rhizoma. The clay contents of subsoil was negatively correlated with the catalpol contents, and positively correlated with the contents of fructose, galactose and sucrose in rhizoma, respectively. The clay contents of soil was positively correlated with the ash contents, and negatively correlated with the contents of ethanol extract and water extract in rhizoma, respectively. The organic matter contents of surface soil and subsoil were negatively correlated with the contents of catalpol and extracts (ethanol and water), and positively correlated with the contents of fructose and ash in rhizoma. The total nitrogen contents of surface soil was negatively correlated with the catalpol contents, and positively correlated with the contents of fructose and sucrose in rhizoma. The potassium contents of soil was highly positively correlated with the fructose contents in rhizoma.

• Journal of Korean Medical classics
• /
• v.9
• /
• pp.432-552
• /
• 1996

The influence of the four noted physicians of Geum-Won era(金元代) on the completion of the medicine in the Chosun dynasty(朝鮮朝) can be summarized as follows. 1. The four noted physicians of Geum-Won era were Yoo-Wan-So(劉完素), Jang-Jong-Jung(張從正), Lee-Go(李杲), Ju-Jin-Heung(朱震亨). 2. Yoo-Wan-So(劉完索) made his theory on the basic of Nae-Kyung("內經") and Sane-Han-Lon("傷寒論"), his idea of medicine was characterized in his books, for exemple, application of O-Oon-Yuk-Ki(五運六氣), Ju-Wha theory(主火論) and hang-hae-seng-je theory(亢害承制論). from his theory and method of study, many deviations of oriental medicine occurred. He made an effort for study of Nae-Kyung, which had been depressed for many years, on the contrary of the way old study that Nae-Kyung had been only explained or revised, he applied the theory of Nae-Kyung to clinical care. The theory of Yuk-Gi-Byung-Gi(六氣病機) and On-Yeul-Byung(溫熱病) had much influenced on his students and posterities, not to mention Jang-Ja-Wha and Ju-Jin-Heung, who were among the four noted physicians therefore he became the father of Yuk-Gi(六氣) and On-Yeul(溫熱) schools. 3. Jang-Jong-Jung(張從正) emulated Yoo-Wan-So as a model, and followed his Yuk-Gi-Chi-Byung(六氣致病) theory, but he insisted on the use of the chiaphoretic, the emetic and the paregoric to get rid of the causes, specially he insisted on the use of the paregoric, so they called him Gong-Ha-Pa(攻下派). He insisted on the theory that if we would strenthen ourselves we should use food, id get rid of cause, should use the paregoric, emetic and diaphoretic. Jang-Jong-Jung'S Gang-Sim-Wha(降心火) theory, which he improved Yoo-Wan-So's Han-Ryang(寒凉) theory influenced to originate Ju-Jin-Heung'S Ja-Eum-Gang-Wha(滋陰降火) theory. 4. Lee-Go(李杲) insisted on the theory that Bi-Wi(脾胃) played a loading role in the physiological function and pathological change, and that the internal disease was originated by the need of Gi(氣) came from the disorder of digestive organs, and that the causes of internal disease were the irregular meal, the overwork, and mental shock. Lee-Go made an effort for study about the struggle of Jung-Sa(正邪) and in the theory of the prescription he asserted the method of Seung-Yang-Bo-Gi(升陽補氣), but he also used the method of Go-Han-Gang-Wha(苦寒降火). 5. The authors of Eui-Hak-Jung-Jun("醫學正傳"), Eui-Hak-Ib-Moon("醫學入門"), and Man-Byung-Whoi-Choon("萬病回春") analyzed the medical theory of the four noted physicians and added their own experiences. They helped organizing existing complicated theories of the four noted physicians imported in our country, and affected the formation of medical science in the Choson dynasty largely. Eui-Hak-Jung-Jun("醫學正傳") was written by Woo-Dan(虞槫), in this book, he quoted the theories of Yoo-Wan-So, Jang-Jong-Jung, Lee-Go, Ju-Jin-Heung, especially, Ju-Jin-Heung was respected by him, it affected the writing of Eui-Lim-Choal-Yo("醫林撮要"). Eui-Hak-ib-Moon("醫學入門"), written by Lee-Chun(李杲), followed the medical science of Lee-Go and ju-jin-heung from the four noted physicians of Geum-Won era. Its characteristics of Taoism, idea of caring of health, and organization affected Dong-Eui-Bo-Kham("東醫寶鑑"). Gong-Jung-Hyun(龔延賢) wrote Man-Byung-Whoi-Choon("萬病回春") using the best part of the theories of Yoo-Wan-So, Jang-Jong-Jung, Lee-Go, Ju-Jin-Heung, this book affected Dong-Eui-Soo-Se-Bo-Won("東醫壽世保元") partly. 6. our medical science was developed from the experience of the treatment of disease obtained from human life, these medical knowledge was arranged and organized in Hyang-Yak-Jib-Sung-Bang("鄕藥集成方"), medical books imported from China was organized in Eui-Bang-Yoo-Chwi("醫方類聚"), which formed the base of medical development in the Chosun dynasty. 7. Eui-Lim-Choal-Yo("醫林撮要") was written by Jung-Kyung-Sun(鄭敬先) and revised by Yang-Yui-Soo(楊禮壽). It was written on the base of Woo-Dan's Eui-Jung-Jun, which compiled the medical science of the four noted physicians of Geum-Won era. It contained confusing theories of the four noted physicians of Geum-Won era and organized medical books of Myung era, therefore it completed the basic form of Byun-Geung-Non-Chi (辨證論治) influenced the writing of Dong-Eui-Bo-Kham("東醫寶鑑"). 8. Dong-Eui-Bo-Kham("東醫寶鑑") was written on the base of basic theory of Eum-Yang-O-Haeng(陰陽五行) and the theory of respondence of heaven and man(天人相應說) in Nae-Kyung. It contained several theories and knowledge, such as the theory of Essence(精), vitalforce(氣), and spirit(神) of Taoism, medical science of geum-won era, our original medical knowledge and experience. It had established the basic organization of our medical science and completed the Byun-Geung-Non-Chi (辨證論治). Dong-Eui-Bo-Kham developed medical science from simple medical treatment to protective medical science by caring of health. And it also discussed human cultivation and Huh-Joon's(許浚) own view of human life through the book. Dong-Eui-Bo-Kham adopted most part of Lee-Go(李杲) and Ju-Jin-Heung's(朱震亨) theory and new theory of "The kidney is the basis of apriority. The spleen is the basis of posterior", so it emphasized the role of spleen and kidney(脾腎) for Jang-Boo-Byung-Gi(臟腑病機). It contained Ju-Jin-Heung's theory of the cause and treatment of disease by colour or fatness of man(black or white, fat or thin). It also contained Ju-Jin-Heung's theory of "phlegm break out fever, fever break out palsy"(痰生熱 熱生風) and the theory of Sang-Wha(相火論). Dong-Eui-Bo-Kham contained Lee-Go's theory of Wha-Yu-Won-Bool-Yang-Lib (火與元氣不兩立論) quoted the theory of Bi-Wi(脾胃論) and the theory of Nae-Oi-Sang-Byun(內外傷辨). For the use of medicine, it followed the theory by Lee-Go. lt used Yoo-Wan-So'S theory of Oh-Gi-Kwa-Keug-Gae-Wi-Yul-Byung(五志過極皆爲熱病) for the treatment of hurt-spirit(傷神) because fever was considered as the cause of disease. It also used Jang-Jons-Jung's theory of Saeng-Keug-Je-Seung(生克制勝) for the treatment of mental disease. 9. Lee-je-ma's Dong-Eui-Soo-Se-Bo-Won("東醫壽世保元") adopted medical theories of Song-Won-Myung era and analyzed these theories using the physical constitutional theory of Sa-Sang-In(四象人). It added Dong-Mu's main idea to complete the theory and clinics of Sa-Sang-Eui-Hak(四象醫學). Lee-Je-Ma didn't quote the four noted physicians of Geum-Won era to discuss that the physical constitutional theory of disease and medicine from Tae-Eum-In(太陰人), So-Yang-In(少陽人), So-Eum-In(少陰人), and Tae-Yang-In(太陽人) was invented from their theories.