• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.3254-3272
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• 2017

With the development of wireless access technologies and the popularity of mobile intelligent terminals, cloud computing is expected to expand to mobile environments. Attribute-based encryption, widely applied in cloud computing, incurs massive computational cost during the encryption and decryption phases. The computational cost grows with the complexity of the access policy. This disadvantage becomes more serious for mobile devices because they have limited resources. To address this problem, we present an efficient verifiable outsourced scheme based on the bilinear group of prime order. The scheme is called the verifiable outsourced computation ciphertext-policy attribute-based encryption scheme (VOC-CP-ABE), and it provides a way to outsource intensive computing tasks during encryption and decryption phases to CSP without revealing the private information and leaves only marginal computation to the user. At the same time, the outsourced computation can be verified by two hash functions. Then, the formal security proofs of its (selective) CPA security and verifiability are provided. Finally, we discuss the performance of the proposed scheme with comparisons to several related works.

• 분석과학
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• 제35권5호
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• pp.189-196
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• 2022

When cationic basic compounds are chromatographed using hydro-organic mobile phase, the presence of anionic free silanols in the silica-based stationary phases results in broad and asymmetrical peaks. The addition of an ionic reagent to the mobile phase prevents analytes from accessing free silanols, improving peak shape. In this study, the chromatographic behavior of salbutamol sulfate as a basic compound was investigated under various conditions, including the use of different columns, mobile phases, and ion-pair reagents such as triethanolamine (TEA) and sodium heptane sulfonate (SHS). The retention and peak shape of chromatograms were both evaluated. The results show that pre-conditioning the column with TEA and including it in the mobile phase can prevent cationic analytes from accessing anionic silanols, resulting in improved peak shape. Furthermore, buffering the mobile phase is an important factor in keeping the pH constant throughout the process. The chosen method was validated in part. This study could be helpful for researchers and analyst to solve such problems with cationic basic components.

• FOCUS: LIFE SCIENCE
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• 제1호
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• pp.5.1-5.3
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• 2024

The document discusses the regeneration of Partisil/Partisphere ion-exchange columns in chromatography. It mentions that column efficiency can diminish with use due to the accumulation of sample and/or mobile phase impurities at the head of the column. This can lead to a change in back pressure, lower column efficiency, and sometimes a change in selectivity. The document outlines a procedure that may restore column performance. The document also provides everyday practices to enhance the lifetime of a column. These include using only high-purity HPLC solvents and buffers, using freshly prepared mobile phases and buffers, filtering mobile phases to remove particulates, using appropriate sample clean-up procedures, using a guard column or pre-column filter, and working within the pressure and flow rate limitations of the column. For the regeneration of Partisil/Partisphere SAX, SCX, WAX, and WCX columns, the document suggests passing 20 column volumes of various mobile phases through the column. These include a buffer wash, distilled water, an acid wash, a chelating wash, a methanol wash, and a buffer for separation. The document emphasizes that not all of these wash steps are required for every column clean-up and that some chromatographers require only a combination of certain steps.

• KSBB Journal
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• 제29권3호
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• pp.205-209
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• 2014

Chromatographic enantiomer resolution of chiral amines was performed on several covalently immobilized and coated chiral stationary phases (CSPs) based on polysaccharide derivatives under the mobile phase conditions containing base or acid or acid/base additive. The chromatographic parameters including separation factors and capacity factors were greatly influenced by the nature of the mobile phase containing base or acid or salt additive as well as the used CSPs. When 0.05% triethylamine/0.05% trifluoroacetic acid as an additive in the mobile phase was used on all CSPs in this study, the greatest enantiomer resolution was observed except for Chiralpak AD. Also, it was shown that the change of base additive into acid or salt in the mobile phase may directly affect chiral recognition mechanisms between the chiral selectors and analytes occurring during enantiomer separation, resulting in the change of elution orders.

• 분석과학
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• 제11권4호
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• pp.292-296
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• 1998

헤테로 고리 화합물인 isoquinoline과 외부치환체로서 $COOCH_3$, CN 및 $CH_3$ 작용기들이 치환된 화합물들의 혼합물을 정상 및 역상법으로 분리 한 결과, 이동상의 종류에 따라 용리순서에 용매화 효과가 나타났다. 또한, 헤테로 고리 화합물 내부의 방향족성이 없는 2-methylindoline과 방향족성이 있는 2-methylindole, 그리고 헤테로 원자가 질소와 산소인 benzoxazole과 질소와 황인 benzothiazole의 머무름거동은 정상 액체 크로마토그래피의 경우 시료 분자와 충진제의 흡착 표면과의 흡착력으로 설명할 수 있었고, 역상 액체 크로마토그래피의 경우는 시료와 정지상과의 소수성 상호작용 등으로 설명할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.539-545
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• 2014

Styrene-acrylamide co-polymer was immobilized on porous partially sub-$2{\mu}m$ silica monolith particles and inner surface of fused silica capillary ($50{\mu}m$ ID and 28 cm length) to result in ${\mu}LC$ and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant ${\mu}LC$ and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW~1500) with good separation efficiency (number of theoretical plates ~300,000/m).

• Bulletin of the Korean Chemical Society
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• 제28권6호
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• pp.1035-1038
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• 2007

• 인터넷정보학회논문지
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• 제15권4호
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• pp.135-140
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• 2014

본 논문에서는 모바일 앱을 위한 개발과정 모델을 제안하였다. 이 개발과정에는 요구분석, 아키텍쳐설계, 네비게이션설계, 페이지 설계 구현과 테스팅 단계를 포함한 다섯가지 개발단계가 있다. 그리고 다이어그램이 있는 설계방법도 제안하였다. 프로그램개발자는 기능적 요구사항과 설계앱을 정의하는데 본 논문에서 제안한 개발방법을 이용할수 있다. 또한 개발시간과 노력을 줄일 수도 있다. 본 논문에서는 모바일 앱 개발에 이 방법을 적용하였고, 개발과정을 수행한 결과물로 다이어그램을 제시하였다.

• ETRI Journal
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• 제19권3호
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• pp.281-302
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• 1997

In this paper, we present three kinds of development support systems (test and evaluation systems), which are developed to fulfill the specific needs in accordance with the CDMA Mobile System (CMS) developmental phases. The support systems consist of the mobile switch traffic simulator (MSTS), the mobile call simulator (MCS), and the CDMA mobile system analysis tools (CSAT). The MSTS is used for the simulation of the base station in the stage of development of the mobile exchange, and the MCS is used for the overall performance test of the CMS. The CSAT is used for the CMS performance evaluation. These systems have been used for the CMS development successfully.

• KSBB Journal
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• 제31권3호
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• pp.186-191
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• 2016

A liquid chromatographic method for the enantiomer separation of fluoxetine was performed using covalently bonded and coated type polysaccharide-derived chiral stationary phases (CSPs). The degree of enantioseparation is affected by the used CSPs and mobile phases. The performance of Chiralpak IC was superior to the other CSPs used in this study. Out of various solvent composition and additives, the greatest separation and resolution was observed using Chiralpak IC with mobile phase of 2-propanol in hexane with diethylamine as an additive. Semi-preparative separation of fluoxetine was performed on the analytical Chiralpak IC column to obtain (R)- and (S)-fluoxetine enantiomer with high chemical and optical purity. From the overall study, the developed liquid chromatographic method on polysaccharide-derived CSPs is expected to be very useful for the enantiomer separation of fluoxetine.