• Journal of the Korea Convergence Society
• /
• v.7 no.5
• /
• pp.161-167
• /
• 2016

Distribution channels are changing its industry paradigm from quantitative increase to qualitative improvement. In addition, it incorporates new characteristics and consumption tread of customers and the core value of service is developing focused around on online to offline (O2O) business model of omnichannel. In this respect, companies are integrating various distribution channels and in order to provide high content business service to customers, their interest in finding a new business strategy is increasing. Currently, most of the service being provided to customers are formed based on distribution structure centered around big companies and financial industry and the problems faced by small to medium and micro enterprises, which are expansion and improvement of channels, discovery of new distribution channels and finding O2O marketing strategy, can be said as very important task. Accordingly, this research purports to create added values which can serve as the driving force of growth of "creative economy" by improving distribution channels in which anyone who incorporates needs of smart consumers can enter into the smart commerce market and to further form sustainable win-win market that is strategic through business platforms for small to medium and micro enterprises therefrom.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.1
• /
• pp.107-114
• /
• 2014

Purpose : The purpose of this study is evaluation for the applicability of O-MAR(Metal artifact Reduction for Orthopedic Implants)(ver. 3.6.0, Philips, Netherlands) in head & neck radiation treatment planning CT with metal artifact created by dental implant. Materials and Methods : All of the in this study's CT images were scanned by Brilliance Big Bore CT(Philips, Netherlands) at 120kVp, 2mm sliced and Metal artifact reduced by O-MAR. To compare the original and reconstructed CT images worked on RTPS(Eclipse ver 10.0.42, Varian, USA). In order to test the basic performance of the O-MAR, The phantom was made to create metal artifact by dental implant and other phantoms used for without artifact images. To measure a difference of HU in with artifact images and without artifact images, homogeneous phantom and inhomogeneous phantoms were used with cerrobend rods. Each of images were compared a difference of HU in ROIs. And also, 1 case of patient's original CT image applied O-MAR and density corrected CT were evaluated for dose distributions with SNC Patient(Sun Nuclear Co., USA). Results : In cases of head&neck phantom, the difference of dose distibution is appeared 99.8% gamma passing rate(criteria 2 mm / 2%) between original and CT images applied O-MAR. And 98.5% appeared in patient case, among original CT, O-MAR and density corrected CT. The difference of total dose distribution is less than 2% that appeared both phantom and patient case study. Though the dose deviations are little, there are still matters to discuss that the dose deviations are concentrated so locally. In this study, The quality of all images applied O-MAR was improved. Unexpectedly, Increase of max. HU was founded in air cavity of the O-MAR images compare to cavity of the original images and wrong corrections were appeared, too. Conclusion : The result of study assuming restrained case of O-MAR adapted to near skin and low density area, it appeared image distortion and artifact correction simultaneously. In O-MAR CT, air cavity area even turned tissue HU by wrong correction was founded, too. Consequentially, It seems O-MAR algorithm is not perfect to distinguish air cavity and photon starvation artifact. Nevertheless, the differences of HU and dose distribution are not a huge that is not suitable for clinical use. And there are more advantages in clinic for improved quality of CT images and DRRs, precision of contouring OARs or tumors and correcting artifact area. So original and O-MAR CT must be used together in clinic for more accurate treatment plan.

• KIISE Transactions on Computing Practices
• /
• v.24 no.1
• /
• pp.40-45
• /
• 2018

With the advent of big data and social networks, large-scale graph processing becomes popular research topic. Recently, an optimization technique called Gorder has been proposed to improve the performance of in-memory graph processing. This technique improves performance by optimizing the graph layout on memory to have better cache locality. However, since it is designed for in-memory graph processing systems, the technique is not suitable for disk-based graph engines; also the cost for applying the technique is significantly high. To solve the problem, we propose a new graph ordering called I/O Order. I/O Order considers the characteristics of I/O accesses for SSDs and HDDs to improve the performance of disk-based graph engine. In addition, the algorithmic complexity of I/O Order is simple compared to Gorder, hence it is cheaper to apply I/O Ordering. I/O order reduces the cost of pre-processing up to 9.6 times compared to that of Gorder's, still its performance is 2 times higher compared to the Random in low-locality graph algorithms.

• Electronics and Telecommunications Trends
• /
• v.27 no.5
• /
• pp.55-63
• /
• 2012

빅데이터 시대를 맞이하여 이를 분석하여 지능형 서비스로 활용할 수 있는 기술로 인공지능 기술이 다시 관심을 받고 있다. 본고에서는 인공지능의 여러 요소 기술 중 기계학습(machine learning) 분야의 빅데이터 처리를 위한 동향을 소개한다. 현재 사용 가능한 병렬처리 기반의 기계학습, 빅데이터를 이용한 기계학습 기반으로 진행되고 있는 프로젝트, 다양한 분야에 쉽게 기계학습을 적용할 수 있는 domain adaptation 기술에 대해서 정리한다.

• Communications for Statistical Applications and Methods
• /
• v.14 no.2
• /
• pp.459-479
• /
• 2007

Theories related to financial market has received big attention from the statistics community. However, not many courses on the topic are provided in statistics departments. Because the financial theories are entangled with many complicated mathematical and physical theories as well as ambiguously stated financial terminologies. Based on our experience on the topic, we try to explain the rather complicated terminologies and theories with easy-to-understand words. This paper will briefly cover the topics of basic terminologies of derivatives, Black-Scholes pricing idea, and related basic mathematical terminologies.

• Proceedings of the Korea Contents Association Conference
• /
• 2018.05a
• /
• pp.497-498
• /
• 2018

4차 산업혁명 시대의 도래에 따라, ICBM(IoT, Cloud, Big-data, Mobile) 기술이 핵심요소로 부각 되고 있으며, 그에 힘입어 부품 제조 산업분야에서도 Idustry4.0 등의 스마트팩토리 기술이 각광을 받고 있다. 본 논문에서는 금형의 설계도면 정보와 그림파일을 수집하여 데이터베이스로 구축하고 사용자가 필요로 하는 금형에 대한 이미지만으로 금형에 대한 정보를 검색하여 매칭시켜 줄 수 있는 모바일 기반의 시스템을 제안한다.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.3
• /
• pp.87-92
• /
• 1997

Inductively coupled Cl$_{2}$ plasma has been studied to etch Pt thin films, which hardly form volatile compound with any reactive gas at normal process temperature. Low etch rate and residue problems are frequently observed. For higher etch rate, high density plasma and higher process temperature is adopted observed. For higher etch rate, high density plasma and higher process temperature is adopted and thus SiO$_{2}$ is used as for patterning mask instead of photoresist. The effect of O$_{2}$ or Ar addition to Cl$_{2}$ was investigated, and the chamber pressure, gas flow rate, surce RF power and bias RF power are also varied to check their effects on etch rate and selectivity. The major etching mechanism is the physical sputtering, but the ion assisted chemical raction is also found to be a big factor. The proposs can be optimized to obtain the etch rate of Pt up to 200nm/min and selectivity to SiO$_{2}$ at 2.0 or more. Patterning of submicron Pt lines are successfully demonstrated.

• Proceedings of the Optical Society of Korea Conference
• /
• 2000.08a
• /
• pp.88-89
• /
• 2000

The properties for self-frequency doubling (SFD) is unique phenomena for a small number of special single crystals. It is known that there are serious limitations to vary the concentration of active ions, for example high doping of active ions from 1 to 50 atomic %, in nonlinear materials. Until now, the Nd:YAl$_3$(BO$_3$)$_4$ (YAB) and Nd:(Ce,Gd)Sc$_3$(BO$_3$)$_4$ (CSB) crystals with high doping rates are well studied for the application of SFD purpose. They have much useful SFD properties, but also have big problems in crystal growth. In case of YAB crystal, it can be grown by solution melt method with very low growth rates and easy occurrence of inclusions. In case of CSB crystal, it has optically heterogeneity problems because of disarrangement of ions in huntite structure [1]. These problems make above crystals not so attractive for optical applications. Some popular nonlinear materials, such as LiNbO$_3$(LN), KTiOPO$_4$(KTP), LiB$_3$O$_{5}$ (LBO) crystals, are impossible to substitute by Rare Earth activators because of their crystallo-chemical problems of structure. When we dope active ions with the requisite concentrations for laser generation, it results in decreasing of optical quality of crystals or destroying of acentrosymmetric structure. (omitted)d)

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.3
• /
• pp.281-287
• /
• 2012

The internal oxide scale of twelve superheater and reheater tubes were tested which were serviced for 30,000~120,000 hours in thermal power plants. The oxide scale was formed in three layers. The Cr-rich area was observed beneath the original metal surface. The hematite ($Fe_2O_3$) phase was formed on the outer surface. The intermediate layer was magnetite ($Fe_3O_4$). The thickness of Cr-rich layer was about half of the total scale. All layers grew during the operation hour of the plant. The thickness of thickest scale was 0.2mm in superheater tubes. This can increase the tube metal temperature about $7^{\circ}C$ more than initial state. $7^{\circ}C$ tube metal temperature can reduce tube life about 30%, but the boiler tube's design margin is big enough therefore it has been analyzed that it would not effect on the life span.

• Korean Journal of Materials Research
• /
• v.21 no.12
• /
• pp.703-707
• /
• 2011

The electrochromic properties of tungsten oxide films grown by RF sputtering were investigated. Among the sputter parameters, first the $Ar:O_2$ ratios were controlled with division into only an $O_2$ environment, 1:1 and 4:1. The structure of each film prepared by these conditions was studied by X-ray diffraction, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. The sputter-deposited tungsten oxide films had an amorphous structure regardless of the $Ar:O_2$ ratios. The chemical compositions, however, were different from each other. The stoichiometric structure and low-density film was obtained at higher $O_2$ contents. Electrochemical tests were performed by cyclic voltammetry and chronoamperometry at 0.05 M $H_2SO_4$ solutions. The current density and charge ratio was estimated during the continuous potential and pulse potential cycling at -0.5 V and 1.8 V, respectively. The film grown in a higher oxygen environment had a higher current density and a reversible charge reaction during intercalation and deintercalation. The in-situ transmittance tests were performed by He-Ne laser (633 nm). At higher oxygen contents, a big transmittance difference was observed but the response speed was too slow. This was likely caused by higher film resistivity. Furthermore, the effect of sputtering pressure was also investigated. The structure and surface morphology of each film was observed by X-ray diffraction and scanning electron microscopy. A rough surface was observed at higher sputtering pressure, and this affected the higher transmittance difference and coloration efficiency.