• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.699-720
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• 1995

This study was conducted to evaluate the effect of benzalkonium chloride solution as a wetting agent instead of water on dentin bonding with NTG-GMA/BPDM system (All-bond 2, Bisco.) and DSDM system (Aelitebond, Bisco.). Benzalkonium chloride solution is a chemical disinfectant widely used in medical and dental clinics for preoperative preparation of skin and mucosa due to its strong effect of cationic surface active detergent. Eighty freshly extracted bovine lower incisor were grinded labially to expose flat dentin surface, and then were acid-etched with 10 % phosphoric acid for 15 second, water-rinsed, and dried for 10 second with air syringe. The specimens were randomly divided into 8 groups of 10 teeth. The specimens of control group were remoistured with water and the specimens of experimental groups were remoistured with 0.1 %, 0.5 %, and 1.0 % benzalkonium chloride solution respectively. And then, the Aelitefil composite resin was bonded to the pretreated surface of the specimens by use of All-bond 2 dentin bonding system or Aelitebond dentin bonding system in equal number of the specimens. The bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, then the tensile bond strength was measured, the mode of failure was observed, the fractured dentin surface were examined under scanning electron microscopy, and FT-IR spectroscopy was taken for the purpose of investigating the changes of the dentin surface pretreated with benzal konium chloride solution followed by each primer of the dentin bonding systems. The results were as follows : In the group of bonding with NTG-GMA/BPDM dentin bonding agent(All-bond 2), higher tensile bond strength was only seen in the experimental group remoistured with 0.1 % benzal konium chloride solution than that in water-remoistured control group(p<0.05). In the group of bonding with DSDM dentin bonding agent (Aelitebond), no significant differences were seen between the control and each one of the experimental group(p<0.05). Higher tensile bond strength were seen in NTG-GMAIBPDM dentin bonding agent group than in DSDM dentin bonding agent group regardless of remoistur ization with benzal konium chloride solution. On the examination of failure mode, cohesive and mixed failure were predominantly seen in the group of bonding with NTG-GMAIBPDM dentin bonding agent, while adhesive failure was predominantly seen in the group of bonding with DSDM dentin bonding agent. On SEM examination of fractured surfaces, no differences of findings of primed dentin surface between the groups with and without remoisturization with benzal konium chloride solution. FT-IR spectroscopy taken from the control and the experimental group reve::.led that some higher absorbance derived from the primers binding to dentin surface was seen at the group pretreated with 0.1 % benzal konium chloride solution than at the control group of remoisturizing with water.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3231-3248
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• 2015

Many IT organizations aspire to improve the efficiency and general standard of their software development effort by implementing agile software development practices. Some of the popular agile development methods adopted by IT organizations are Scrum, eXtreme Programming (XP), Kanban, Featured Driven Development (FDD) and Dynamic System Development Method (DSDM). This paper intends to identify and analyze the barriers that impact on the performance of IT organizations that use such agile software development methods. The analysis will help the IT organizations to cater the needed aspects to be successful. The analysis will also help the IT organizations to select the right methodology for their organization. The contribution of this analysis is to present guideline related to avoid or overcome the barriers towards adoption of agile.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.851-855
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• 2009

In this paper, the Agile Framework for Small Projects (AFSP) was applied to four industry cases. The AFSP provides a structured way for software organizations to adopt agile practices and evaluate the results. The framework includes an extended serum process and agile practices, based on agility and critical success factors in agile software projects that are selected from Serum, XP, FDD, DSDM and Crystal Clear. The case projects were evaluated, and the analysis of the results clearly showed that the framework used in the aforementioned cases displayed a high degree of efficiency.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.54-61
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• 2009

This paper proposes the 2nd-order SDSDM (Space Dithered Sigma-Delta Modulation) for performance improvement of a buck converter. The PWM (Pulse Width Modulation) has a drawback in that power spectrum tends to be concentrated around the switching frequency. The resulting harmonic spikes cause a EMI(Electromagnetic Interference) and switching loss in semiconductor, etc. The 1st-order SDSDM scheme is a kind of DSDM for reducing these harmonic spikes. In this scheme, a switching frequency is spread through random dither generator placed on input part. In experimental result, the proposed 2nd-order SDSDM is confirmed by applying to a buck converter.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.13-27
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• 2014

Agile methodologies have gained recognition as efficient development processes through their quick delivery of software, even under time constraints. However, like other agile methods such as Scrum, Extreme Programming (XP) and The Dynamic Systems Development Method (DSDM), Feature Driven Development (FDD) has been criticized due to the unavailability of security elements in its twelve practices. In order to examine this matter more closely, we conducted a systematic literature review (SLR) and studied literature for the years 2001-2012. Our findings highlight that, in its current form, the FDD model partially supports the development of secure software. However, there is little research on this topic, as detailed information about the usage of secure software is rarely published. Thus, we have been able to conclude that the existing five phases of FDD have not been enough to develop secure software until recently. For this reason, security-based phase and practices in FDD need to be proposed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.646-663
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• 2014

Scrum is one of the most popular and efficient agile development methods. However, like other agile methods such as Extreme Programming (XP), Feature Driven Development (FDD), and the Dynamic Systems Development Method (DSDM), Scrum has been criticized because of lack of support to develop secure software. Thus, in 2011, we published research proposing the idea of a security backlog (SB). This paper represents the continuation of our previous research, with a focus on the evaluation in industry-based case study. Our findings highlight an improved agility in Scrum after the integration of SB. Furthermore, secure software can be developed quickly, even in situations involving requirement changes of software. Based on our experimental findings, we noticed that, when integrating SB, it is quite feasible to develop secure software using an agile Scrum model.

• Journal of Power Electronics
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• v.9 no.5
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• pp.667-678
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• 2009

The PWM (Pulse Width Modulation) control signals have a drawback in that their power spectrum tends to be concentrated around the switching frequency and the resulting harmonic spikes cause an EMI (Electromagnetic Interference) and switching losses in semiconductors, etc. The SDM (Sigma-Delta Modulation) is a type of switching modulation used to reduce these harmonic spikes, and several SDM schemes are investigated in this paper. In the DSDM (Dithered SDM), the SDSDM (Space-Dithered SDM) and TDSDM (Time-Dithered SDM), the signals are classified by the location of their random dither additions. In these schemes, the switching frequency is spread by a random dither generator placed on the input or the output parts. Experimental results are presented where the advantages of the new proposed CDSDM (Combined Dithered SDM) are confirmed by applying to a buck converter.

• Journal of Information Processing Systems
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• v.9 no.1
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• pp.69-88
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• 2013

Agile methods are highly attractive for small projects, but no agile method works well as a standalone system. Therefore, some adaption or customization is always required. In this paper, the Agile Framework for Small Projects (AFSP) was applied to four industry cases. The AFSP provides a structured way for software organizations to adopt agile practices and evaluate the results. The framework includes an extended Scrum process and agile practices, which are based on agility and critical success factors in agile software projects that are selected from Scrum, XP, FDD, DSDM and Crystal Clear. AFSP also helps software managers and developers effectively use agile engineering techniques throughout the software development lifecycle. The case study projects were evaluated on the basis of risk-based agility factors, the agility of the adopted practices, agile adoption levels, and the degree of the agile project success. The analysis of the results showed that the framework used in the aforementioned cases was effective.

• The Journal of Society for e-Business Studies
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• v.2 no.1
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• pp.53-77
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• 1997

This paper presents an efficient methodology for information system development by adopting the concept of extended components which can achieve the improvement of development productivity, reductrion of development time periods, quality improvement of information systems, etc. when information development projects are carried out. First of all, for efficient development of information systems, development steps of current methodologies for information system analysis are subdivided into components in detail and outputs required at each step are defined. The components are extended by types and various application methods are proposed in each step of information system development. In addition, a method which uses advantages of current methods such as SDLC, prototyping, and RAD, is also proposed. In this research, a CASE tool named S-Designer is used for the development of extended components and their interface, and a system development method called DSDM for the deviation of detailed steps and corresponding outputs.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.196-198
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• 2008

본 논문에서는 강압형 DC-DC 컨버터의 성능 개선을 위한 스위칭 기법인 2차 SDSDM(Space Dithered Sigma-Delta Modulation)방식을 제안한다. PWM 방식은 일정 스위칭 주파수 대역에서의 고조파로 인해 소음, 전자파 장애, 스위칭 손실 등을 초래한다. 이러한 문제를 해결하기 위한 DSDM 방식의 일종인 1차 SDSDM은 랜덤 디더(Random Dither) 발생기가 1차 SDM의 양자화기(quatizer) 입력 단에 위치하여 스위칭 주파수가 분산된다. 강압형 DC/DC 컨버터에 제안하는 2차 SDSDM의 방식을 적용한 실험 결과를 통해 타당성을 검증한다.