• 제목/요약/키워드: GroupExplorer

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In-Space Performance of "KAGUYA" Lunar Explorer Propulsion Subsystem

  • Masuda, Ideo;Goto, Daisuke;Kagawa, Hideshi;Kajiwara, Kenichi;Sasaki, Takeshi;Tamura, Masayuki;Takahashi, Mamoru;Kasuga, Kazuhito;Ikeda, Mizuho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 한국추진공학회 2008년 영문 학술대회
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    • pp.407-412
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    • 2008
  • "KAGUYA"(SELENE) is a Japanese Lunar Explorer launched by H-IIA rocket from Tanegashima Space Center on 14 September 2007. The dual-mode bipropellant propulsion subsystem of KAGUYA includes two fuel tanks, an oxidizer tank, propellant and pressurant control components, twelve monopropellant 20N thrusters, eight monopropellant 1N thrusters, and a bipropellant 500N Orbit Maneuver Engine(OME). Once the KAGUYA separated from the rocket, it circled the Earth twice and traveled to the Moon, where it entered lunar orbit. All maneuvers were performed through multiple 500N OME/20N thruster firings. This paper describes the in-space performance of KAGUYA Lunar Explorer bipropellant propulsion subsystem.

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Supporting Group Workspaces Based on WebDAV (웹데브 기반의 그룹 작업공간 지원)

  • Kim Dong-Ho;Shin Won-Joon;Park Jin-Ho;Lee Myung-Joon
    • The KIPS Transactions:PartC
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    • 제13C권4호
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    • pp.521-532
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    • 2006
  • WebDAV is an IETF standard protocol which support asynchronous collaborative authoring on the Web. The recently published WebDAV Access Control Protocol provides various methods of controlling the resources on a WebDAV server and their properties, helping high-level group activities to be performed through the WebDAV server. Based on the WebDAV access control protocol, we developed Group Workspaces which support exchanging and/or sharing data among the group members. Any member of a Group Workspace can create and share resources among the members. Also, any member can add, change or delete the resources. To support the Group Workspaces, we developed a client application named GroupExplorer, which solely supports Group Workspaces. We constructed the server for Group Workspaces using Jakarta Slide - a WebDAV server supporting the WebDAV Access Control Protocol.

Effect of different provisional cement remnant cleaning procedures including Er:YAG laser on shear bond strength of ceramics

  • Zortuk, Mustafa;Gumus, Hasan Onder;Kilinc, Halil Ibrahim;Tuncdemir, Ali Riza
    • The Journal of Advanced Prosthodontics
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    • 제4권4호
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    • pp.192-196
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    • 2012
  • PURPOSE. The purpose of this study was to evaluate the effect of provisional cement removal by different dentin cleaning protocols (dental explorer, pumice, cleaning bur, Er:YAG laser) on the shear bond strength between ceramic and dentin. MATERIALS AND METHODS. In total, 36 caries-free unrestored human third molars were selected as tooth specimens. Provisional restorations were fabricated and cemented with eugenol-free provisional cement. Then, disc-shaped ceramic specimens were fabricated and randomly assigned to four groups of dentin cleaning protocols (n = 9). Group 1 (control): Provisional cements were mechanically removed with a dental explorer. Group 2: The dentin surfaces were treated with a cleaning brush with pumice Group 3: The dentin surfaces were treated with a cleaning bur. Group 4: The provisional cements were removed by an Er:YAG laser. Self-adhesive luting cement was used to bond ceramic discs to dentin surfaces. Shear bond strength (SBS) was measured using a universal testing machine at a 0.05 mm/min crosshead speed. The data were analyzed using a Kolmogorov Smirnov, One-way ANOVA and Tukey HSD tests to perform multiple comparisons (${\alpha}$=0.05). RESULTS. The dentin cleaning methods did not significantly affect the SBS of ceramic discs to dentin as follows: dental explorer, pumice, cleaning bur, and Er:YAG laser. CONCLUSION. The use of different cleaning protocols did not affect the SBS between dentin and ceramic surfaces.

Clinical Effect of MS Coat and Elmex gel on the Dentin Hypersensitivity following Periodontal Surgery (치주수술 후 지각과민증에 대한 MS Coat와 엘멕스 겔처치의 임상적 효과)

  • Park, Sung-Min;Lim, Sung-Bin;Chung, Chin-Hyung
    • Journal of Periodontal and Implant Science
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    • 제31권4호
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    • pp.727-736
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    • 2001
  • Dentinal hypersensitivity is one of the complicated symptom rather than a disease. It has special reaction or pain over uncovered root by heat, mechanical or chemical stimulations, which are normal with healthy teeth, The purpose of this study is to discover rather MS Coat (oxalate-containing pre-polymerized resin suspension) or Elmex gel(amine fluoride+sodium fluoride) is effective on hypersensitivity after periodontal treatment using NRS(Numerica1 Rating Scales), which it is useful for evaluating pain level. This study has been prepared in Dankook Dental Hospital with generally healthy adult who had been suffered from dentinal hypersensitivity after periodontal treatment. Divided in three groups with saline(control group), MS Coat(test 1 group) and Elmex gel(test 2 group). And then, following evaluations were made at the end of 1 minute, 1 week, 1 month and 3 months. 1. The sequence of higher frequency & severeness of hypersensitivity is water within $7^{\circ}C$, air stream & explorer. 2. As time goes on, 1 minute, 1 week, 1 month & 3 months, severeness of hypersensitivity scored lower with water, air stream and explorer. 3. With explorer, the differences among three groups as time had to seen. 4. With air stream, the sensitivity scored lower after 1min with MS Coat, Elmex, and saline sequence. As time goes on the sensitivity was lower with MS Coat and Elmex than saline, but there was no difference between MS Coat and Elmex. 5. With water in $7^{\circ}C$, the sensitivity was much decreasing with MS Coat and Elmex than saline, but there was no difference between MS Coat and Elmex. As the result, MS Coat and Elmex are effective on hypersensitivity caused by periodontal treatment.

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Effect of lining application techniques on microleakage in class II composite restorations (다양한 방식으로 적용한 이장재가 2급와동 복합레진 수복의 미세누출에 미치는 영향)

  • Hwang, Byung-Moon;Kim, Joo-Hyung;Park, Ji-Man;Millstein, Philip;Park, Eun-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • 제30권2호
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    • pp.145-151
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    • 2014
  • Purpose: The purpose of this study was to investigate the microleakage in class II cavity resin restorations used with resin-modified glass ionomer (RMGI) lining material depending on two different applying methods; classical delivery method using a dental explorer and a specially designed rotating bur. Materials and Methods: A total thirty-six extracted teeth were prepared with a class II proximal box, and randomly divided into three groups: 1) control group with no lining added and the proximal box restored (Group I), 2) the second group used RMGI as a lining material which was spread with an explorer (Group II), 3) the third group used a specially designed rotating bur to thin out RMGI (Group III). All teeth were restored with the same manner using incrementally placed resin composite. All 36 teeth were prepared and sectioned for the dye penetration test, and observed with a stereomicroscope for scoring the dye penetration. Results: When RMGI liners were used, both groups using an explorer and the special bur with the liner had significantly less microleakage than the control group with no liner (P < 0.05). The 50% of the group with RMGI liner using the bur showed no microleakage under a dye penetration test whereas all the teeth in control group showed microleakage of different degrees. However, there was no statistically significant difference between Group II and Group III. Conclusion: RMGI is an effective lining material to decrease microleakage in class II composite resin restorations regardless of applying methods.

Diversification Strategy through Market Creation: The Case of CJ Group

  • Jeong, Jaeseok;Kim, Nam Jung;Lim, Hyunjoo;Kang, Hyoung Goo;Moon, Junghoon
    • Asia Marketing Journal
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    • 제15권4호
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    • pp.1-32
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    • 2014
  • The purpose of this paper is to investigate upon a diversification strategy through market creation of CJ Group, which has contributed in positioning of the firm as one of the leading conglomerates in South Korea. With such objective, the background of CJ Group, followed by its business diversification strategies were explored, with reference to several case studies. The history of CJ Group began with establishment of CheilJedang Industrial Corporation in 1953, as the first domestic sugar producer and exporter of South Korea. The corporation gradually expanded its business ever since at both national and global level, to include the fields of food production, pharmaceutical, biotechnology, and life chemicals. Later, CheilJedang (CJ) Group was established as an affiliate of CheilJedang Industrial Corporation. With such independence, extension of business has been witnessed across the industries of media, entertainment, finance, information technology and distribution. Thus, the current CJ Group pursues to define itself as a progressive global living culture company with four major business categories from food and food service, biotechnology, entertainment and media, and logistics. Despite its success in today's market, CJ Group underwent hardships in its business diversification in 1990s due to indiscreet management, along with the Asian financial crisis. Here, many firms overcame the financial difficulties by taking advantage of the exchange rate for overseas expansion. Though, CJ Group tried to differentiate itself by focusing on the domestic market by creating something out of nothing. Hence, CJ Group takes a unique position among many cases of business diversification and their categorization. In an effort to identify and classify the types of growth experienced by the top 30 companies in South Korea, the firms were categorized into four groups according to their diversification strategies adapted after the Asian financial crisis. Based on the mode and time of entry, corporations were identified either as the 'Explorer', 'Invader', 'Venture Capitalist', or 'Assimilator'. Here, the majority of the firms showed the qualities of Invader, entering mature markets through large-scaled mergers and acquisitions. However, CJ Group was the only firm that was categorized as an Explorer, for its focus on the newly emerging service sector in culture-contents industry. This diversification strategy through market creation is worth examining, due to its contribution in generating simultaneous growth between the market and the company itself. Diverse brands of CJ Group have been referred to as case studies in this regard, from 'Hatban', 'Cine de Chef', 'VIPS' to 'CJ GLS'. These four businesses, each to represent processed food, film, restaurant service, and logistics industries respectively, show CJ Group's effectiveness in creating a whole new category of goods and services that are innovative. In fact, such businesses not only contributed in advancement of consumers' wellbeing, but toward generating additional value and employment. It is true that the diversification strategy of CJ Group requires long-term capital investment with high risk, compared to the other strategies mentioned in the paper. However, this model does create high employment and additional values that are positive to both the society and the firm itself. Therefore, the paper comes to a conclusion that the diversification strategy through market creation conveys the most positive impact relative to the others.

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Hierarchical Structure of Star-Forming Regions in the Local Group

  • Kang, Yongbeom;Bianchi, Luciana;Kyeong, Jaeman;Jeong, Hyunjin
    • The Bulletin of The Korean Astronomical Society
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    • 제39권2호
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    • pp.60.2-60.2
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    • 2014
  • Hierarchical structure of star-forming regions is widespread and may be characteristic of all star formation. We studied the hierarchical structure of star-forming regions in the Local Group galaxies (M31, M33, Phoenix, Pegasus, Sextans A, Sextans B, WLM). The star-forming regions were selected from Galaxy Evolution Explorer (GALEX) far-UV imaging in various detection thresholds for investigating hierarchical structure. We examined the spatial distribution of the hot massive stars within star-forming regions from Hubble Space Telescope (HST) multi-band photometry. Small compact groups arranged within large complexes. The cumulative mass distribution follows a power law. The results allow us to understand the hierarchical structure of star formation and recent evolution of the Local Group galaxies.

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What Do MIR Properties of Galaxies in the Coma Supercluster Tell Us?

  • Lee, Gwang-Ho;Lee, Myung Gyoon
    • The Bulletin of The Korean Astronomical Society
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    • 제40권1호
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    • pp.76.3-77
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    • 2015
  • MIR colors are an excellent tool to investigate the transition phase of galaxy evolution in terms of star formation at various phases. The Coma supercluster is the nearest massive supercluster, hosting two main clusters, the Coma (Abell 1656) and Leo (Abell 1367) clusters, and one galaxy group, the NGC 4555 group, providing an ideal laboratory to study how galaxies evolve depending on environment. We present the results of a study for MIR properties of galaxies in the Coma supercluster using multi-wavelength data from the optical to MIR including the Sloan Digital Sky Survey Data Release 12 and the Wide-field Infrared Survey Explorer. We investigate differences in MIR properties of galaxies among three galaxy systems, and discuss the results in relation with star formation history and morphological transformation of galaxies.

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A Mid-infrared View on the Fast Galaxy Evolution in Compact Groups

  • Lee, Gwang-Ho;Hwang, Ho Seong;Sohn, Jubee;Lee, Myung Gyoon
    • The Bulletin of The Korean Astronomical Society
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    • 제41권2호
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    • pp.34.2-34.2
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    • 2016
  • We study the mid-infrared (MIR) properties of galaxies in compact groups and their environmental dependence using the Wide-field Infrared Survey Explorer data. We use a sample of 670 compact groups and their 2175 member galaxies with $M_r$ < -19 and 0.01 < z < 0.0741 from Sohn et al. (2016), which were identified through a friends-of-friends algorithm. We find that the MIR [3.4]-[12] colors of early-type galaxies in compact groups are on average bluer than those of early-type galaxies in clusters. Furthermore, we find that when compact groups have both early- and late-type member galaxies, the MIR colors of the late-type galaxies in those compact groups can be bluer than those of late-type galaxies in clusters. We also find that as background galaxy number densities of compact groups increase, compact group galaxies have higher early-type galaxy fractions and bluer MIR colors. These trends are also seen for background galaxies. However, at a given background density, compact group galaxies always have higher early-type galaxy fractions and bluer MIR colors than the background galaxies. Our findings suggest that the properties of compact group galaxies depend on both internal and external environments of the compact groups, and that galaxy evolution is faster in compact groups than in clusters.

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An Ultraviolet Study of Star-Forming Regions in M33

  • Kang, Yongbeom;Rey, Soo-Chang;Bianchi, Luciana
    • The Bulletin of The Korean Astronomical Society
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    • 제41권2호
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    • pp.62.3-63
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    • 2016
  • We studied the young stellar populations of star-forming (SF) regions in M33 based on the Galaxy Evolution Explorer (GALEX) ultraviolet (UV) imaging data. The SF regions are defined from far-UV data with various thresholds. We examined the reddening and spatial distribution of hot massive stars within SF regions from Hubble Space Telescope multi-band survey and Local Group Galaxy Survey (LGGS) data. The H-alpha sources from the LGGS are used for comparing with the spatial distribution of SF regions. The GALEX UV flux measurements of SF regions are used to derive their ages and masses. We also estimated the size and density of SF regions. The younger and compact SF regions are often arranged within older and sparser SF complexes. The results allow us to understand the hierarchical star formation and recent evolution of M33.

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