• 대한화학회지
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• 제55권5호
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• pp.733-740
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• 2011

Multiple regression analysis was used for the calculation of pKa values of 15 substituted benzaldoximes by using various types of descriptors as parameters. These descriptors are based on quantum mechanical treatments. They were derived by employing semi-empirical calculation represented by the PM3 model and an Abinitio method expressed by Hartree-Fock(HF) model performed at the 6-311 G(d, p) level of theory. The parameters tested for their ability to represent the variations observed in the experimental pKa(s) are atomic and structural properties including Muliken charges on the atoms of hydroxyl group and C=N bond, the angle $C_6-C_1-C_7$, and length of O-H bond. Molecular properties are also used like energies of HOMO and LUMO, hardness(${\eta}$), chemical potential(${\mu}$), total energy(TE), dipole of molecule(DM), and electrophilicity index(W). The relation between pKa values and each of these parameters of the studied compounds is investigated. Depending on these relations, two sets of parameters were constructed for comparison between the PM3 and HF methods. The results obtained favor the Abinitio method for such applications although both models proved to have high predictive power and have sufficient reliability to describe the effect of substituents on pKa values of benzaldoxime compounds under consideration which is clear from the values of correlation coefficient $R^2$ obtained and the consistency between the experimental and the calculated values.

• 전기학회논문지
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• 제61권5호
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• pp.744-752
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• 2012

In this study, the Polynomial-based Radial Basis Function Neural Networks is proposed as an one of the recognition part of overall face recognition system that consists of two parts such as the preprocessing part and recognition part. The design methodology and procedure of the proposed pRBFNNs are presented to obtain the solution to high-dimensional pattern recognition problems. In data preprocessing part, Principal Component Analysis(PCA) which is generally used in face recognition, which is useful to express some classes using reduction, since it is effective to maintain the rate of recognition and to reduce the amount of data at the same time. However, because of there of the whole face image, it can not guarantee the detection rate about the change of viewpoint and whole image. Thus, to compensate for the defects, Linear Discriminant Analysis(LDA) is used to enhance the separation of different classes. In this paper, we combine the PCA&LDA algorithm and design the optimized pRBFNNs for recognition module. The proposed pRBFNNs architecture consists of three functional modules such as the condition part, the conclusion part, and the inference part as fuzzy rules formed in 'If-then' format. In the condition part of fuzzy rules, input space is partitioned with Fuzzy C-Means clustering. In the conclusion part of rules, the connection weight of pRBFNNs is represented as two kinds of polynomials such as constant, and linear. The coefficients of connection weight identified with back-propagation using gradient descent method. The output of the pRBFNNs model is obtained by fuzzy inference method in the inference part of fuzzy rules. The essential design parameters (including learning rate, momentum coefficient and fuzzification coefficient) of the networks are optimized by means of Differential Evolution. The proposed pRBFNNs are applied to face image(ex Yale, AT&T) datasets and then demonstrated from the viewpoint of the output performance and recognition rate.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2322-2328
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• 2010

A multiple solid-phase extraction (SPE) method was used with liquid chromatography, coupled with mass spectrometry (LC/MS), for the analysis of heterocyclic amines (HCAs) in human urine. Separation efficiencies based on the pH of the mobile phase and the types of columns were compared. An amide column showed better baseline separation and narrower HCA peak widths at pH 5.0 for the mobile phase than a $C_8$ column. Each SPE step, HLB, MCX, and HybridSPE, was optimized by controlling the pH conditions. The combined method with the three SPEs effectively removed interfering species that cause ion-suppression during HCA detection. Validation of the method, performed with SIM and SRM detection, showed correlation coefficients above 0.991 in the range 0.3 - 16.7 ng/mL. Recovery rates were 45.4 - 97.3% on the $C_8$ column and 71.8 - 101.4% on the amide column, and method detection limits were 0.11 - 0.65 ng/mL on the $C_8$ column and 0.12 - 0.48 ng/mL on the amide column. This method using multiple SPEs offers significant benefits for high-throughput determination of HCAs in urine.

• 한국의류산업학회지
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• 제22권6호
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• pp.844-852
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• 2020

This study is to understand the preferences of pilots, flight engineers and crew who work in the same aircraft but are exposed to different working environments and perform different mission operations in order to develop an ergonomic flight jacket. Based on a preliminary investigation, a survey of 107 pilots and 36 flight engineers and crew was conducted. The results are as follows; Pilots can control the temperature inside the cockpit, so they are less exposed to the cold when working, while flight engineers and crew are exposed to the cold more because they have many external tasks. The reason for the problem of the current flight jacket was a difference in ranking between two groups, but the highest ranking was poor dimensional suitability due to the habit of wearing layers of clothing. As a result of preferred design, there were significant differences between groups in the item of overall style. Pilots preferred a bomber jacket style(P:68.2%, E&C:44.4%), on the other hand, flight engineers and crew preferred a field jacket style(P:26.2%, E&C:55.6%)(p<.01). They preferred a stand collar(P:71.0%, E&C:86.1%), a fastener slider for a front fastening(P:62.6%, E&C:61.1%), fastener tape cuffs(P:54.2%, E&C:47.2%), a jacket with a softshell(P:86.9%, E&C:83.3%), fleece as softshell material(P:88.8%, E&C:69.4%), and fastener sliders as a attaching method(P:69.2%, E&C:61.1%). A hem fastening will be selected differently according to the overall style of outshell. Additionally, they preferred more than 5ea pockets(P:51.4%, E&C:44.4%), fastener sliders as pocket's fastenings(P:48.6%, E&C:61.1%), armpit ventilations(P:62.9%, E&C:58.5%). The results of above will be considered to design an ergonomic flight jacket.

• 한국정보시스템학회지:정보시스템연구
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• 제15권1호
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• pp.1-20
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• 2006

Peer-to-peer systems (P2P) are rapidly growing in importance on the Internet environment, quickly extending the range of their usage. However, peer-to-peer systems have not been widely applied in electronic commerce because they have not been established as an appropriate business model. Therefore, we firstly review the previous research relevant to peer-to-peer systems, and then analyze the business models for P2P systems presented by previous researchers. Furthermore, this study categorizes major issues in terms of the technical and business model aspects. On the basis of these reviews, we develop P2P electronic commerce systems based on the file sharing method between users, focusing on user interface friendliness. A developed P2P electronic commerce systems are programmed by using the C# based on the Microsoft.net solution. A database is implemented using the MSSQL2000. A main application technology is designed that P2P electronic commerce systems make it possible. for user to extend into BtoB Solution by using WSDL (Web Services Description Language), UDDI (Universal Description, Discovery, and Integration) and the XML that is a document for users. User interface is made as form of Internet messenger for a user's convenience and is possible to develop into a commodity transaction system based on XML. In this study, it is possible for the P2P electronic commerce system to have extended application to fields such as Internet shopping mall and property transaction in a nonprofit organization, a public institution and a large scale nonprofit institution that have a similar structure as compared with a structure of a nonprofit educational institution.

• 한국지반공학회논문집
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• 제23권7호
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• pp.87-98
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• 2007

본 연구에서는 DMT를 이용한 비배수 전단강도를 파악하기 위하여 부산신항 점토층에 DMT 시험, 베인전단시험, $CK_0U$ 삼축압축시험을 실시하였다. 시험결과 정규화한 비배수 전단강도비는 삼축시험의 경우 $S_{u(CKU)}/{\sigma}'_v=0.30{\sim}0.35$, 베인전단시험의 경우 ${\mu}S_{u(VST)}/{\sigma}'_v=0.20{\sim}0.22$로 나타났다. 본 연구에서는 현장 베인전단시험 및 삼축압축시험 결과와의 비교를 통해, DMT를 이용하여 비배수 전단강도를 추정하는 두 가지 방법을 제안하였다. 첫 번째는 $S_u/{\sigma}'_v$와 횡방향 응력지수의 관계를 이용하는 방법이고, 두 번째는 $N_c-I_D$ 또는 $N_c-E_D$ 관계로부터 비배수 전단강도를 추정하는 방법이다. 베인전단시험 및 삼축시험 결과와 두 가지 추정방법을 비교한 결과, $N_c-I_D$ 또는 $N_c-E_D$ 관계를 이용한 방법이 $K_D$ 이용하는 방법보다 비배수 전단강도를 정확하게 추정하는 것으로 나타났다. 이것은 $I_D$와 $E_D$가 토질상태를 반영하는 $p_1-p_0$항을 포함하고 있어, $N_c$를 이용하는 방법이 토질을 고려한 비배수 전단강도 추정을 할 수 있기 때문으로 판단된다.

• 인터넷정보학회논문지
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• 제23권5호
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• pp.103-110
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• 2022

봇넷은 금전적인 요구부터 국가적 위협에 이르는 다양한 목적을 위해 악용되어왔으며 사이버보안 분야에서 가장 위협적인 공격 유형 중 하나이다. 봇넷은 초창기 중앙집중식 구조로 출현한 이후 P2P 구조로 발전되어 왔다. 비트코인은 2008년 Satoshi Nakamoto가 발표한 최초의 블록체인 기술 기반의 온라인 암호화폐로 전 세계에서 가장 널리 통용되고 있는 암호화폐이며 비트코인 사용자가 증가함에 따라 비트코인 네트워크는 더욱 확장되고 있다. 이에 따라, 비트코인 네트워크를 C&C 채널로 사용하는 봇넷이 등장했으며 최근에는 다양한 연구가 수행되고 있다. 본 연구에서는 비트코인 환경에서 암호화된 봇넷 C&C 통신 메커니즘과 기법을 제안하고 비트코인 테스트넷에서 실제로 구축한 후 다양한 실험을 통해 성능평가를 해봄으로써 제안 기법의 유효성을 확인하고 궁극적으로는 비트코인 네트워크에서의 봇넷 위협의 가능성과 대응 필요성을 알리고자 한다.

• Food Science and Biotechnology
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• 제17권4호
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• pp.892-894
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• 2008

During dongchimi fermentation at 5 and $25^{\circ}C$, the pH lowered slowly and reached 4.03 at $5^{\circ}C$ after 30 days, whereas it lowered dramatically and reached 3.59 at $25^{\circ}C$ after 2 days. The predominant bacteria were Leuconostoc (Leu.) mesenteroides at $25^{\circ}C$ until day 2 which changed into Lactobacillus (Lb.) plantarum at day 3, analyzed by a culture dependent method with partial 16S rRNA gene sequencing, whereas Leu. mesenteroides occupied predominantly at $5^{\circ}C$ until day 7. In a culture-independent method using a polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) with partial 16S rRNA gene sequencing, Lb. algidus was predominant at $5^{\circ}C$ until day 7 and Lb. plantarum occupied predominantly at $25^{\circ}C$ until day 3, which is different from the results of the culture based method, indicating the both methods need to be combined for accuracy. Based on the culture-dependent method, Leu. mesenteroides might be responsible for the early and mid-phase of dongchimi fermentation.

• Structural Engineering and Mechanics
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• 제4권2호
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• pp.177-190
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• 1996

A method to numerically evaluate the behaviour of single span beams, prestressed with external tendons and symmetrically loaded is presented. This algorithm, based on the Finite Difference Method, includes second order effects and large displacements in an attempt to more fully understand the behaviour of the beam up to collapse. The numerical technique discussed is particularly appropriate for the analysis of R.C. and P.C. beams rehabilitated or strengthened by means of external prestressing but it is reliable for the analysis of new beams as well.

• 핵의학기술
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• 제13권1호
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• pp.98-103
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• 2009

Purpose: Correct estimation of Glomerular filtration rate (GFR) is very important for an accurate clinical assessment of the kidney function. This study compares four GFR markers, a serum creatinine-based estimation using MDRD formula, Cystatin-C, Cr-51 EDTA 2 samples and 6 samples. Materials and Methods: Serum creatinine concentrations, Cystatin-C serum concentrations and Cr-51 EDTA clearance are measured in 43 patients who received or donated kidney. Results: The correlation coefficient between serum based estimated GFR (MDRD) and Cr-51 EDTA 6 samples was 0.817 (p<0.01). The correlation coefficient between Cystatin-C based GFR and EDTA 6 samples was 0.7322 (p<0.01). Regression analysis showed a statistically significant correlation between Cr-51 EDTA 2 samples and 6 samples (r=0.971, p<0.01). Mean value and ${\pm}2SD$ for the difference between Cr-51 EDTA 2 samples and 6 samples were 4.7 mL/min and ${\pm}9.3$ respectively. Conclusions: The estimation of two samples Cr-51 EDTA showed that the method can be simplified by reducing blood samples without losing its high accuracy.