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Methodology for Issue-related R&D Keywords Packaging Using Text Mining (텍스트 마이닝 기반의 이슈 관련 R&D 키워드 패키징 방법론)

  • Hyun, Yoonjin;Shun, William Wong Xiu;Kim, Namgyu
    • Journal of Internet Computing and Services
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    • v.16 no.2
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    • pp.57-66
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    • 2015
  • Considerable research efforts are being directed towards analyzing unstructured data such as text files and log files using commercial and noncommercial analytical tools. In particular, researchers are trying to extract meaningful knowledge through text mining in not only business but also many other areas such as politics, economics, and cultural studies. For instance, several studies have examined national pending issues by analyzing large volumes of text on various social issues. However, it is difficult to provide successful information services that can identify R&D documents on specific national pending issues. While users may specify certain keywords relating to national pending issues, they usually fail to retrieve appropriate R&D information primarily due to discrepancies between these terms and the corresponding terms actually used in the R&D documents. Thus, we need an intermediate logic to overcome these discrepancies, also to identify and package appropriate R&D information on specific national pending issues. To address this requirement, three methodologies are proposed in this study-a hybrid methodology for extracting and integrating keywords pertaining to national pending issues, a methodology for packaging R&D information that corresponds to national pending issues, and a methodology for constructing an associative issue network based on relevant R&D information. Data analysis techniques such as text mining, social network analysis, and association rules mining are utilized for establishing these methodologies. As the experiment result, the keyword enhancement rate by the proposed integration methodology reveals to be about 42.8%. For the second objective, three key analyses were conducted and a number of association rules between national pending issue keywords and R&D keywords were derived. The experiment regarding to the third objective, which is issue clustering based on R&D keywords is still in progress and expected to give tangible results in the future.

EFFECT OF LIGHT IRRADIATION MODES ON THE MARGINAL LEAKAGE OF COMPOSITE RESIN RESTORATION (광조사 방식이 복합레진 수복물의 변연누출에 미치는 영향)

  • 박은숙;김기옥;김성교
    • Restorative Dentistry and Endodontics
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    • v.26 no.4
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    • pp.263-272
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    • 2001
  • The aim of this study was to investigate the influence of four different light curing modes on the marginal leakage of Class V composite resin restoration. Eighty extracted human premolars were used. Wedge-shaped class Y cavities were prepared on the buccal surface of the tooth with high-speed diamond bur without bevel. The cavities were positioned half of the cavity above and half beyond the cemento-enamel junction. The depth, height, and width of the cavity were 2 mm, 3 mm and 2 mm respectively. The specimens were divided into 4 groups of 20 teeth each. All the specimen cavities were treated with Prime & Bond$^{R}$ NT dental adhesive system (Dentsply DeTrey GmbH, Germany) according to the manufacturer's instructions and cured for 10 seconds except group VI which were cured for 3 seconds. All the cavities were restored with resin composite Spectrum$^{TM}$ TPH A2 (Dentsply DeTrey GmbH, Germany) in a bulk. Resin composites were light-cured under 4 different modes. A regular intensity group (600 mW/${cm}^2$, group I) was irradiated for 30 s, a low intensity group (300 mW/${cm}^2$, group II) for 60 s and a ultra-high intensity group (1930 mW/${cm}^2$, group IV) for 3 s. A pulse-delay group (group III) was irradiated with 400 mW/${cm}^2$ for 2 s followed by 800 mW/${cm}^2$ for 10 s after 5 minutes delay. The Spectrum$^{TM}$ 800 (Dentsply DeTrey GmbH, Germany) light-curing units were used for groups I, II and III and Apollo 95E (DMD, U.S.A.) was used for group IV. The composite resin specimens were finished and polished immediately after light curing except group III which were finished and polished during delaying time. Specimens were stored in a physiologic saline solution at 37$^{\circ}C$ for 24 hours. After thermocycling (500$\times$, 5-55$^{\circ}C$), all teeth were covered with nail varnish up to 0.5 mm from the margins of the restorations, immersed in 37$^{\circ}C$, 2% methylene blue solution for 24 hours, and rinsed with tap water for 24 hours. After embedding in clear resin, the specimens were sectioned with a water-cooled diamond saw (Isomet$^{TM}$, Buehler Co., Lake Bluff, IL, U.S.A.) along the longitudinal axis of the tooth so as to pass the center of the restorations. The cut surfaces were examined under a stereomicroscope (SZ-PT Olympus, Japan) at ${\times}$25 magnification, and the images were captured with a CCD camera (GP-KR222, Panasonic, Japan) and stored in a computer with Studio Grabber program. Dye penetration depth at the restoration/dentin and the restoration/enamel interfaces was measured as a rate of the entire depth of the restoration using a software (Scion image, Scion Corp., U.S.A.) The data were analysed statistically using One-way ANOVA and Tukey's method. The results were as follows : 1. Pulse-Delay group did not show any significant difference in dye penetration rate from other groups at enamel and dentin margins (p>0.05) 2. At dentin margin, ultra-high intensity group showed significantly higher dye penetration rate than both regular intensity group and low intensity group (p<0.05). 3. At enamel margin, there were no statistically significant difference among four groups (p>0.05). 4. Dentin margin showed significantly higher dye penetration rate than enamel margin in all groups (p<0.05).

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FRACTURE RESISTANCE OF THE THREE TYPES OF UNDERMINED CAVITY FILLED WITH COMPOSITE RESIN (복합 레진으로 수복된 세 가지 첨와형태 와동의 파절 저항성에 관한 연구)

  • Choi, Hoon-Soo;Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.33 no.3
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    • pp.177-183
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    • 2008
  • It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel, undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesiodistally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference in fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even if that portion consists of mainly enamel and a little dentin structure.

The influence of occlusal loads on stress distribution of cervical composite resin restorations: A three-dimensional finite element study (교합력이 치경부 복합레진 수복물의 응력분포에 미치는 영향에 관한 3차원 유한요소법적 연구)

  • Park, Chan-Seok;Hur, Bock;Kim, Hyeon-Cheol;Kim, Kwang-Hoon;Son, Kwon;Park, Jeong-Kil
    • Restorative Dentistry and Endodontics
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    • v.33 no.3
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    • pp.246-257
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    • 2008
  • The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering, Inc., Troy, USA) and ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Vivadent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition, Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

Structural change and electrical conductivity according to Sr content in Cu-doped LSM (La1-xSrxMn0.8Cu0.2O3) (Sr 함량이 Cu-doped LSM(La1-xSrxMn0.8Cu0.2O3)의 구조적변화와 전기전도도에 미치는 영향)

  • Ryu, Ji-Seung;Noh, Tai-Min;Kim, Jin-Seong;Lee, Hee-Soo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.22 no.2
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    • pp.78-83
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    • 2012
  • The structural change and the electrical conductivity with Sr content in $La_{1-x}Sr_xMn_{0.8}Cu_{0.2}O_3$ (LSMCu) were studied. $La_{0.8}Sr_{0.2}MnO_3$ (LSM) and $La_{1-x}Sr_xMn_{0.8}Cu_{0.2}O_3$ ($0.1{\leq}x{\leq}0.4$) were synthesized by EDTA citric complexing process (ECCP). A decrease in the lattice parameters and lattice volumes was observed with increase of Sr content, and these results were attributed to the increasing $Mn^{4+}$ ions and $Cu^{3+}$ ions in B-site. The electrical conductivity measured from $500^{\circ}C$ to $1000^{\circ}C$ was increased with increase of Sr content in the $0.1{\leq}x{\leq}0.3$ composition range, and it was 172.6 S/cm (at $750^{\circ}C$) and 177.7 S/cm (at $950^{\circ}C$, the maximum value) in x = 0.3. The electrical conductivity was decreased in x = 0.4 because of the presence of the second phase in the grain boundaries. The lattice volume was contracted by increase of $Mn^{4+}$ ions and $Cu^{3+}$ ions in B-site according to increase of Sr content and the electrical conductivity was increased with increase of charge carriers which were involved in the hopping mechanism.

Developmental competence and Effects of Coculture after Crypreservation of Blastomere-Biopsied Mouse Embryos as a Preclinical Model for Preimplantation Genetic Diagnosis (착상 전 유전진단 기술 개발의 동물실험 모델로서 할구 생검된 생쥐 배아에서 동결보존 융해 후 배아 발생 양상과 공배양 효과에 관한 연구)

  • Kim, Seok-Hyun;Kim, Hee-Sun;Ryu, Buom-Yong;Choi, Sung-Mi;Pang, Myung-Geol;Oh, Sun-Kyung;Jee, Byung-Chul;Suh, Chang-Suk;Choi, Young-Min;Kim, Jung-Gu;Moon, Shin-Yong;Lee, Jin-Yong;Chae, Hee-Dong;Kim, Chung-Hoon
    • Clinical and Experimental Reproductive Medicine
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    • v.27 no.1
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    • pp.47-57
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    • 2000
  • Objective: The effects of cryopreservation with or without coculture on the in vitro development of blastomere-biopsied 8-cell mouse embryos were investigated. This experimental study was originally designed for the setup of a preclinical mouse model for the preimplantation genetic diagnosis (PGD) in human. Methods: Eight-cell embryos were obtained after in vitro fertilization (IVF) from F1 hybrid mice (C57BL(표현불가)/CBA(표현불가)). Using micromanipulation, one to four blastomeres were aspirated through a hole made in the zona pellucida by zona drilling (ZD) with acid Tyrode's solution (ATS). A slow-freezing and rapid-thawing protocol with 1.5M dimethyl sulfoxide (DMSO) and 0.1M sucrose as cryoprotectant was used for the cryopreservation of blastomere- biopsied 8-cell mouse embryos. After thawing, embryos were cultured for 110 hours in Ham's F-10 supplemented with 0.4% bovine serum albumin (BSA). In the coculture group, embryos were cultured for 110 hours on the monolayer of Vero cells in the same medium. The blastocyst formation was recorded, and the embryos developed beyond blastocyst stage were stained with 10% Giemsa to count the total number of nuclei in each embryo. Results: The survival rate of embryos after cryopreservation was significantly lower in the blastomere-biopsied (7/8, 6/8, 5/8, and 4/8 embryos) groups than in the non-biopsied, zona intact (ZI) group. Without the coculture, the blastocyst formation rate of embryos after cryopreservation was not significantly different among ZI, the zona drilling only (ZD), and the balstomere-biopsied groups, but it was significantly lower than in the non-cryopreserved control group. The mean number of cells in embryos beyond blastocyst stage was significantly higher in the control group ($50.2{\pm}14.0$) than in 6/8 ($26.5{\pm}6.2$), 5/8 ($25.0{\pm}5.5$), and 4/8 ($17.8{\pm}7.8$) groups. With the coculture using Vero cells, the blastocyst formation rate of embryos after cryopreservation was significantly lower in 5/8 and 4/8 groups, compared with the control, 7/8, and 6/8 groups. The mean number of cells in embryos beyond blastocyst stage was also significantly lower in 4/8 group ($25.9{\pm}10.2$), compared with the control ($50.2{\pm}14.0$), 7/8 ($56.0{\pm}22.2$), and 6/8 ($55.3{\pm}25.5$) groups. Conclusion: After cryopreservation, blastomere-biopsied mouse embryos have a significantly impaired developmental competence in vitro, but this detrimental effect might be prevented by the coculture with Vero cells in 8-cell mouse embryos biopsied one or two blastomeres. Biopsy of mouse embryos after ZD with ATS is a safe and highly efficient preclinical model for PGD of human embryos.

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Tensile Bond Strength of Composite Resin Treated with Er:YAG Laser (Er:YAG 레이저를 활용한 와동형성시 컴포짓 결합강도)

  • Shin, Min;Ji, Young-Duk;Rhu, Sung-Ho;Cho, Jin-Hyoung
    • Journal of Oral Medicine and Pain
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    • v.30 no.2
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    • pp.269-276
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    • 2005
  • This in vitro study evaluated the influence of a flowable composite resin on the tensile bond strength of resin to enamel and dentin treated with Er:YAG laser and diamond bur. 96 Buccal enamel and mid-coronal dentin were laser-irradiated using an Er:YAG laser and treated with diamond bur. Each groups(48) were divided two small groups depends on acid-etching procedure. Light-cure flowable resin(Metafil Flo) and self-cure resin(Clearfil FII New Bond) were used in this study. After surface etching with 37% phosphoric acid and the application of an adhesive system, specimens were prepared with a hybrid composite resin. After 24hours storage in distilled water at 37$^{\circ}C$, all samples were submitted to the tensile bond strength evaluation, using a universal testing machine(Z020, Zwick, Germany). The obtained results were as follows: 1. TBS of acid-etching group were higher than those of non-etching group in both enamel and dentin treated with Er:YAG laser and diamond bur. Laser 'conditioning' was clearly less effective than acid-etching. Moreover, acid etching lased enamel and dentin significantly improved the microTBS of M-Flo. 2. In enamel, TBS of laser-irradiated group were lower than those of bur-prepared group. However, in flowable resin subgroup, there were not differed those between two groups in dentin. 3. In laser-treated group, TBS of flowable composite resin were higher than those of self-curing resin in dentin, however, there was no difference in enamel. From this study, we can conclude that the self- and light-cure composite resin bonded significantly less effective to lased than to bur-cut enamel and dentin, and that acid-etch procedure remains mandatory even after laser ablation. We suggest that Er:YAG laser was useful for preparing dentin cavity with flowable resin filling.

The Rooting Ability of Selected Clones of Populus alba×glandulosa Hybrid (Populus alba×glandulosa의 Clone간(間) 발근력(發根力)의 차이(差異))

  • Kim, Chung-Suk;Son, Doo-Sik;Chung, Sang-Bae
    • Journal of Korean Society of Forest Science
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    • v.38 no.1
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    • pp.19-26
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    • 1978
  • In order to investigate the difference of rootability between 15 clones of Populus alba${\times}$glandulosa selected based on the growth performance, rooting of cutting experiments with these 15 clones were conducted at the nursery for six years from 1970 to 1975. Cutting experiments in a temperature controlled incubator in which the temperature of the cutting bed were set to $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ were also performed. Along with these experiments air layering experiments were performed to compare with the rootabilities obtained from nursery trial. The results obtained so far could be summarized as follows. 1. The best rooting clones were 65-22-4 and 65-22-11, and the average rooting percentages of these two clones for six years were 76.7%, and 72.9% respectively. The poorest rooting clone was 66-6-8 showing average rooting percentage of 45.8%. 2. The middle class of rooting percentage was ocuppied by the clones; 66-14-29, 66-14-93, 66-25-5 and 67-6-3, and the range of their rooting percentage was 60~69% on average. 3. The rooting performances observed through the nursery, the incubator and the air layering experiments were almost the same with exception of few clones. 4. P. alba${\times}$glandulosa showed the best rooting percentage at the cutting bed of $20^{\circ}C$ 5. The most roots, i.e. 78.5% of root per cutting were developed from the bottom part of the cutting shoot. 6. Adventitious and call use roots could observe in the cuttings.

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Effects of Controlling the Pine Needie Gall Midaes by Salicylic Acid Content in Needles of Some Pinus spp. (소나무류(類) 침엽내(針葉內)의 salicylic acid에 의한 솔잎혹파리의 방제효과(防除效果))

  • Son, Doo-Sik;Eom, Tae-Jin;Choi, Chang-Ok;Zhang, Ruo Ming
    • Journal of Korean Society of Forest Science
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    • v.88 no.1
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    • pp.31-37
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    • 1999
  • The frequency of gall formation by pine needle gall midges ranged from 35% to 40% in both P. densiflora and P. thunbergii species. However, there was no indication of gall development from larva on both P. virgiana and P. rigida species suggesting that some specific compounds might play role in preventing gall formation of larva. The susceptible species to pine needle gall midges including P. densiflora and P. thunbergii contained a little salicylic acid under the free phenolic compound conditions while the resistant species against such insects including P. virginiana and P. rigida species contained about 37ppm to 50ppm of salicylic acid. Thus, this compound might have important roles in insect resistance. The contents of internal salicylic acid in the needles of susceptible pines increased from 9.5ppm to 20.6ppm after direct external irrigation of salicylic acid solution and flour treatment on roots. As a result, the frequency of gall formation decreased dramatically 17~19 times lower when compared with that of control. According to our results, the application of salicylic acid for effective prevention against insect damages should be performed before hatching eggs. The frequency of gall formation in the hybrid pines of P. thunbergii(susceptible) and P. virginiana(resistant) showed approximately 24% as average value of those in both species. In the case of specific individuals, it ranged from 2.8% to 11.5% in hybrids of both species. Therefore, effective production of insect resistant pines can be obtained through hybrids by crossing between susceptible and resistant species including P. thunbergii and P. virginiana by increasing internal salicylic acid contents of the needles.

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Predicting the Performance of Recommender Systems through Social Network Analysis and Artificial Neural Network (사회연결망분석과 인공신경망을 이용한 추천시스템 성능 예측)

  • Cho, Yoon-Ho;Kim, In-Hwan
    • Journal of Intelligence and Information Systems
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    • v.16 no.4
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    • pp.159-172
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    • 2010
  • The recommender system is one of the possible solutions to assist customers in finding the items they would like to purchase. To date, a variety of recommendation techniques have been developed. One of the most successful recommendation techniques is Collaborative Filtering (CF) that has been used in a number of different applications such as recommending Web pages, movies, music, articles and products. CF identifies customers whose tastes are similar to those of a given customer, and recommends items those customers have liked in the past. Numerous CF algorithms have been developed to increase the performance of recommender systems. Broadly, there are memory-based CF algorithms, model-based CF algorithms, and hybrid CF algorithms which combine CF with content-based techniques or other recommender systems. While many researchers have focused their efforts in improving CF performance, the theoretical justification of CF algorithms is lacking. That is, we do not know many things about how CF is done. Furthermore, the relative performances of CF algorithms are known to be domain and data dependent. It is very time-consuming and expensive to implement and launce a CF recommender system, and also the system unsuited for the given domain provides customers with poor quality recommendations that make them easily annoyed. Therefore, predicting the performances of CF algorithms in advance is practically important and needed. In this study, we propose an efficient approach to predict the performance of CF. Social Network Analysis (SNA) and Artificial Neural Network (ANN) are applied to develop our prediction model. CF can be modeled as a social network in which customers are nodes and purchase relationships between customers are links. SNA facilitates an exploration of the topological properties of the network structure that are implicit in data for CF recommendations. An ANN model is developed through an analysis of network topology, such as network density, inclusiveness, clustering coefficient, network centralization, and Krackhardt's efficiency. While network density, expressed as a proportion of the maximum possible number of links, captures the density of the whole network, the clustering coefficient captures the degree to which the overall network contains localized pockets of dense connectivity. Inclusiveness refers to the number of nodes which are included within the various connected parts of the social network. Centralization reflects the extent to which connections are concentrated in a small number of nodes rather than distributed equally among all nodes. Krackhardt's efficiency characterizes how dense the social network is beyond that barely needed to keep the social group even indirectly connected to one another. We use these social network measures as input variables of the ANN model. As an output variable, we use the recommendation accuracy measured by F1-measure. In order to evaluate the effectiveness of the ANN model, sales transaction data from H department store, one of the well-known department stores in Korea, was used. Total 396 experimental samples were gathered, and we used 40%, 40%, and 20% of them, for training, test, and validation, respectively. The 5-fold cross validation was also conducted to enhance the reliability of our experiments. The input variable measuring process consists of following three steps; analysis of customer similarities, construction of a social network, and analysis of social network patterns. We used Net Miner 3 and UCINET 6.0 for SNA, and Clementine 11.1 for ANN modeling. The experiments reported that the ANN model has 92.61% estimated accuracy and 0.0049 RMSE. Thus, we can know that our prediction model helps decide whether CF is useful for a given application with certain data characteristics.