추천시스템의 효과적 도입을 위한 소셜네트워크 분석

박종학(Jong Hak Park*),조윤호(Yoonho Cho) 한국지능정보시스템학회 2011 지능정보연구 Vol.17 No.4

협업필터링은 다양한 분야에서 널리 활용되고 있지만 협업필터링의 추천 성능은 적용하는 기업의 비즈니스 형태나 발생하는 거래 데이터의 특성에 따라 다르게 나타나고 있다. 기업에서 협업필터링 추천시스템을 구축하려면 상당한 시간과 비용이 소요되기 때문에 구축된 추천시스템의 성과가 높지 않다면 기업 자원의 낭비를 초래할 뿐만 아니라 부정확한 추천서비스를 받는 고객들의 불만을 살 수 있다. 따라서 추천시스템 도입을 검토할 때 기업이 갖고 있는 데이터의 특성을 파악하고 이를 통해 추천시스템을 도입하는 것이 타당한지 사전에 예측할 수 있다면 불필요한 도입으로 인한 경제적 손실과 고객 만족도 저하를 막을 수 있을 것이다. 기존 연구에서는 협업필터링 추천 성과에 희박성, 우연성, 커버리지 등이 영향을 미칠 수 있다고 설명하고 있지만 이러한 요인들이 어떻게 얼마나 추천 성과에 영향을 미치는지, 요인들 간에 어떠한 상관관계가 있는지는 현재까지 구체적으로 밝혀진 바가 없다. 본 연구에서는 구매 트랜잭션으로부터 생성된 소셜네트워크로부터 밀도, 군집화계수, 집중도 등의 구조적 지표를 측정한 후 이들이 추천성과에 어떻게 영향을 미치는지 통계적 분석을 통해 실증적으로 규명한다. 이를 통해 협업필터링 추천시스템에 대한 도입 여부를 결정하고자 할 때 유용하게 사용될 수 있는 지침을 제공하고자 한다.

가공 전차선로 구성체의 금속부식에 관한 고찰

박종학(Jong-Hak Park),최용은(Yong-Eun Choi),오효석(Hyo-Seok Oh),이재봉(Jae-Bong Lee),김재문(Jae-Moon Kim),강정원(Geong-Won Kang) 대한전기학회 2022 대한전기학회 학술대회 논문집 Vol.2022 No.5

첨가제에 따른 염산시부트라민 정제의 특성화 및 방출거동

박종학 ( Jong Hak Park ),구정 ( Jung Ku ),안식일 ( Sik Il Ahn ),이준희 ( Jun Hee Lee ),김윤태 ( Yun Tae Kim ),김대성 ( Dae Sung Kim ),김원 ( Won Kim ),이종문 ( John M Rhee ),강길선 ( Gilson Khang ) 한국조직공학·재생의학회 2008 조직공학과 재생의학 Vol.5 No.4

In this study, sibutramine HCl, appetite suppressants were prepared into tablet type with additives such as lactose monohydrate, microcrystalline cellulose(MCC), and PVP K-25 to effective oral administration. We used the polyplasdone XL-10 as disintegrant. We compared the in vitro release behavior of sibutramine from the tablets according to additives with commercial drug, Reductil. The change of structure and crystallinity of tablet by additives were characterized by fourier-transform infrared spectroscopy(FT-IR) and differential scanning calorimeter( DSC). FT-IR and DSC results demonstrates that structure of drug was changed and crystallinity of drug was decreased according to additives. The dissolution rate of sibutramine HCl from tablet greatly increased in simulated gastric fluid(pH 1.2) and simulated intestinal fluid(pH 6.8) in case of adding lactose monohydrate and PVP K-25. This study suggest that various pharmaceutical excipients could improve the sibutramine HCl release behaviors.

수용성 고분자에 따른 실로스타졸 고체분산체의 특성화 및 조절된 방출거동

박종학 ( Jong Hak Park ),김세호 ( Se Ho Kim ),오재민 ( Jae Min Oh ),안식일 ( Sik Il Ahn ),김윤태 ( Yun Tae Kim ),정수현 ( Su Hyun Jung ),최진희 ( Jin Hee Choi ),이동원 ( Dong Won Lee ),유일수 ( Il Sou Yoo ),이종문 ( John M Rhee ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.4

The aim of this study was to improve dissolution rate and controlled release of poorly water-soluble drug, cilostazol, using general water soluble polymers. We prepared solid dispersed cilostazol with hydrophilic polymer, Poly-N-Vinylpyrolidone(PVP), Plasdone S630, Hydroxypropylmethylcellulose(HPMC), PEG 6000, Eudragit E100, and surfactant, Poloxamer 407. Characterization of cilostazol solid dispersion analyzed by scanning electron microscope(SEM), differential scanning calorimeter(DSC) and infrared spectrometry(FT-IR). SEM and DSC were found that amorphous in solid dispersion. Particle size analyzer was used to investigate size of cilostazol in solid dispersion. The in vitro release behavior of solid dispersion presented at simulated gastric fluid(pH 1.2). The release behavior of cilostazol was controlled release with hydrophilic polymers and solid dispersed cilostazol with hydrophilic polymers was sustained release behavior than initial burst release of commercial drug(Pletal(R)). This studies suggest that this solid dispersion system with hydrophilic polymers controlled poorly water-soluble drug, cilostazol, release behaviors.

디자인의 동일 또는 유사 여부 판단

박종학(Jong Hak Park) 세창출판사 2010 창작과 권리 Vol.- No.60

Modern society is product-oriented one. Various products that are manufactured and sold stimulate consumers' desire. Hence, the manufacturer tries to make products that are equipped with beautiful appearance as well as excellent quality and functions. For consumers, who want to express their personalities through their products as a total fashion, regards a design on their products as an important decision factor for buying the products. This design is created from constant research and efforts, not naturally. Strong legal protection for the design is required because the design, which is difficult to be created, is easy to be copied. Therefore, design protection law tightly protects an issued design: applied designs which is same and similar with publically-known, publically-used ones are denied due to lack of novelty. In this context, it is important legal issue to determine whether the compared designs are same or similar each other because this sameness or similarity is used when determining novelty of design, pre-application, expanded pre-application. Also, they are used when determining the scope of the issued design's right and protection. It is highly important to legal theory and solution for legal dispute to study on the criteria of design's sameness and similarity, which is the most important factor for design protection. In addition, more understanding for new cases is required in the legal system of design protection law and intellectual property law. Also, more leading cases, which do not harm legal stability and seek detailed plausibility, are needed to be settled.

염산 트라마돌을 함유하는 PLGA 미립구의 제조 및 방출거동

박종학 ( Jong Hak Park ),엄신 ( Shin Eom ),안식일 ( Sik Il Ahn ),김대성 ( Dae Sung Kim ),김원 ( Won Kim ),이동원 ( Dong Won Lee ),유일수 ( Il Sou Yoo ),이종문 ( John M Rhee ),강길선 ( Gil Son Khang ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.4

Tramadol HCl(TH)-loaded poly(L-lactide-co-glycolide)(PLGA) microspheres were prepared by O/O solvent evaporation method for sustained release. We investigated the release behavior according to PLGA molecular weight and concentration. TH-loaded PLGA microspheres were characterized on the surface and cross-section morphology by SEM. TH-loaded PLGA microspheres had smooth surfaces and various pores in internal structure. As the PLGA molecular weight and PLGA concentration increased, the release rate of TH decreased. The behaviors of degradation was decreased according to increased PLGA molecular weight. These results showed that the release behaviors can be controlled by various of molecular weight and concentration of PLGA.

사회연결망:신규고객 추천문제의 새로운 접근법

박종학(Jong Hak Park),조윤호(Yoon Ho Cho),김재경(Jae Kyeong Kim) 한국지능정보시스템학회 2009 지능정보연구 Vol.15 No.1

협업필터링은 상품을 추천하고자 하는 고객과 유사한 구매 행태를 보이는 고객들의 구매 정보를 반영하여 추천대상 고객이 아직 구매하지 않은 상품에 대한 선호도를 예측한 후 선호도가 높을 것으로 예측되는 상품을 추천해주는 시스템이다. 그러나 신규고객의 경우에는 과거 구매 이력의 부재로 선호도를 예측할 수 없어 추천이 어렵게 되는 신규고객 추천문제가 발생하게 된다. 이러한 신규고객 추천문제를 해결하기 위해 기존에 제시되었던 방법들은 추천의 정확도가 낮거나, 추천에 필요한 정보 획득이 어렵거나, 추천 전에 고객이 능동적으로 질의에 응답해야 하는 부담이 있는 등의 문제로 인하여 그 실효성이 매우 낮다. 따라서 기존의 신규고객 추천 방법의 한계를 극복할 수 있는 새로운 접근방법의 필요성이 대두되고 있다. 본 연구에서는 사회네트워크 분석에서 관계 ? 구조적 특성을 분석하기 위해 널리 활용 되고 있는 중심성 개념을 협업필터링에 적용하여 신규고객의 이웃고객을 찾고 그 이웃고객들의 구매정보를 이용하여 신규고객에게 상품을 추천하는 방법을 제시한다. 추천 프로세스는 구매 유사도 분석, 고객 네트워크 구성, 이웃고객 형성, 신규고객 상품추천 단계로 구성된다. 제시한 추천방법의 성능을 평가하기 위하여 국내 유명 백화점 중의 하나인 H백화점의 고객 구매 데이터를 사용하여 실험하였다. 실험 결과로부터 제시한 추천방법이 기존의 신규고객 추천방법들과 비교하여 추천의 정확도는 높으면서도, 구매정보 외에 인구통계정보 등과 같은 추가 정보가 필요하지 않으며, 추천 전에 고객이 능동적으로 질의에 응답할 필요가 없는 새로운 방법임을 알 수 있었다. Collaborative filtering recommends products using customers’ preferences, so it cannot recommend products to the new customer who has no preference information. This paper proposes a novel approach to new customer recommendations using the social network analysis which is used to search relationships among social entities such as genetics network, traffic network, organization network, etc. The proposed recommendation method identifies customers most likely to be neighbors to the new customer using the centrality theory in social network analysis and recommends products those customers have liked in the past. The procedure of our method is divided into four phases:purchase similarity analysis, social network construction, centrality-based neighborhood formation, and recommendation generation. To evaluate the effectiveness of our approach, we have conducted several experiments using a data set from a department store in Korea. Our method was compared with the best-seller-based method that uses the best-seller list to generate recommendations for the new customer. The experimental results show that our approach significantly outperforms the best-seller-based method as measured by F1-measure.

도시철도 고압배전케이블의 열화진단에 관한 고찰

박종학(Jong-Hak Park),오효석(Hyo-Seok Oh),장진영(Chin-Young Chang),강정원(Geong-Won Kang) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.5

배전용 고압 케이블은 전기적, 열적 특성이 우수한 가교 폴리에틸렌을 절연체로 하는 가교폴리에틸렌 절연비닐 시스 케이블(이하, CV케이블)이 주류를 이루고 있으며, 고압 케이블의 특징과 열화진단의 필요성에 대하여 고찰하고자 한다.

복부 자상환자의 처치에 대한 응급의학에서의 고찰

박종학 ( Jong Hak Park ),김정윤 ( Jung Youn Kim ),신준현 ( Jun Hyun Shin ),윤영훈 ( Young Hoon Yoon ),조한진 ( Han Jin Cho ),문성우 ( Sung Woo Moon ),최성혁 ( Sung Hyuk Choi ),이성우 ( Sung Woo Lee ),홍윤식 ( Yun Sik Hong ) 대한외상학회 2010 大韓外傷學會誌 Vol.23 No.1

Purpose: In Korea, most abdominal penetrating wounds are caused by stab wounds rather than gun-shot wounds. However, not many studies have been performed on stab injuries and their epidemiologic characteristics. Disagreements of opinions of obligatory surgical exploration and conservative treatment exist, and this subject is still being debated. Therefore, the authors studied the epidemiologic characteristics of abdominal stab wound patients visiting the emergency department and reviewed the proportion of patients that received nontherapeutic surgery and conservative treatment. Methods: This study included patients visiting the emergency department with abdominal stab wounds. A retrospective chart review was done on the abdominal stab wound patients. Sex, age, cause of injury, location of wound, initial vital signs, operation results, injured organs and CT & LWE results were reviewed. Results: The median age of the 121 patients was 40.9 years, of these patients, 88 were males, of which 52 (43.0%) were drunken. Of the patients that received non-therapeutic operations, only 3 patients (15.0%) were drunken, significantly lower than the therapeutic operation group. For the location of the wound, most patients were injured in the right and left upper quadrants, 27 patients each. The most common injured organ was the small bowel; 13 patients were injured in the small bowel. With abdominal CT scans and local wound explorations together, the results exhibited a sensitivity of 97%, a specificity of 44%, a positive predictive value of 56%, and a negative predictive value of 95%. Conclusion: In our study, the sensitivity was 97% when CT & LWE were performed together; thus we can conclude that CT and LWE can be used together to select the treatment method. Although in our study, the surgical indications in abdominal stab wound patients is not sufficient, our results showed a higher rate of nontherapeutic surgery compared to previous studies. Therefore, more research is needed to prevent unnecessary laparotomies in hemodynamically-stable patients without symptoms. (J Korean Soc Traumatol 2010;23:21-28)

염산 랄록시펜 고체분산체의 특성 및 용출율 개선

박종학 ( Jong Hak Park ),김세호 ( Se Ho Kim ),안식일 ( Sik Il Ahn ),최진희 ( Jin Hee Choi ),이준희 ( Jun Hee Lee ),김윤태 ( Yun Tae Kim ),김대성 ( Dae Sung Kim ),김원 ( Won Kim ),이동원 ( Dong Won Lee ),이종문 ( John M Rhee ),강길선 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.1

Poorly water-soluble drug, Raloxifene HCl, is a selective estrogen receptor modulator(SERM) and is currently being used for prevention of osteoporosis in postmenopausal women. We prepared solid dispersion with hydrophilic polymer, polyvinylpyrrolidone(PVP), and surfactant, Poloxamer 407, to improve the solubility of drug. Characterization of raloxifene HCl solid dispersion analyzed by scanning electron microscope(SEM) and Fourier transform infrared spectrometry(FT-IR). SEM and FT-IR were found that raloxifene HCl is amorphous and hydrogen bonding between drug and polymer in solid dispersion. The in vitro release behavior of solid dispersion presented at simulated gastric fluid(pH 1.2) and simulated intestinal fluid(pH 6.8). The dissolution rate of raloxifene HCl was dramatically higher than commercial drug(Evista(R)). This studies suggest that this solid dispersion system improved the bioavailability of poorly water-soluble drug, such as raloxifene HCl.