• Title/Summary/Keyword: 선택적 공유

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Competition Policy and Open Access to Essential Facilities in Natural Gas Market (천연가스시장 경쟁도입과 필수설비 공유의 효과 분석)

  • Heo, Eun Jeong;Cho, Myeonghwan
    • Environmental and Resource Economics Review
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    • v.29 no.1
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    • pp.47-89
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    • 2020
  • We introduce a simple theoretical model to analyze the welfare impact of a competition policy in the natural gas market in South Korea. An incumbent monopolistic firm currently owns essential facilities, but the competition policy mandates that the firm provide open access to any entrant firm, charging an access fee. When no regulation is imposed on the fee pricing, this policy increases social welfare as well as the profit of the incumbent firm. When the pricing is regulated, however, social welfare depends on whether there is information asymmetry between the government and the firm regarding the operating cost of the facilities. If the government has complete information, social welfare can be maximized by choosing the optimal prices. Otherwise, the government has to set the prices based on the information that the firm delivers. We formulate a Bayesian game to analyze this case and identify a set of perfect Bayesian equilibria to compare social welfare.

Graft Considerations for Successful Anterior Cruciate Ligament Reconstruction (성공적인 전방십자인대 재건술을 위한 적절한 이식건의 선택)

  • Kyung, Hee-Soo
    • Journal of the Korean Orthopaedic Association
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    • v.56 no.1
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    • pp.14-25
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    • 2021
  • Several factors need to be considered for a successful anterior cruciate ligament (ACL) reconstruction, such as preoperative planning, operation technique, and postoperative rehabilitation. Graft choice, fixation, preparation method, maturation, incorporation to host bone, and graft tension should also be considered to achieve a good outcome after an ACL reconstruction. Factors to consider when selecting a graft are the graft strength, graft fixation, fixation site healing, and donor site morbidity, as well as the effects of initial strength, size, surface area, and origin of the graft on its potential for weakening during healing. There are two types of graft for an ACL reconstruction, autograft or allograft. Several autografts have been introduced, including the bone-patellar tendon-bone, hamstring tendon, and quadriceps tendon-bone. On the other hand, each has its advantages and disadvantages. The recent increased use of allografts for an ACL reconstruction is the lack of donor site morbidity, decreased surgical time, diminished postoperative pain, and good availability of source. Despite this, there are no reports suggesting that an allograft may have a better long-term outcome than an autograft. Allografts have inherent disadvantages, including a longer and less complete course of incorporation, remodeling, biomechanically inferiority to autograft, the potential risk of an immunogenic reaction and disease transmission. Higher long-term failure rates and poorer graft maturation scores were reported for allografts compared to autografts. An autograft in an ACL reconstruction should remain the gold standard, although the allograft is a reasonable alternative. If adequate length and diameter of autograft can be obtained for an ACL reconstruction, an autograft with adequate graft fixation and postoperative rehabilitation should be chosen instead of an allograft to achieve better results.

Research trend of Web 2.0 use in education (웹 2.0의 교육적 활용에 대한 연구 동향 분석: 블로그와 위키를 중심으로)

  • Heo, Hee-Ok;Kang, Eui-Sung
    • The Journal of Korean Association of Computer Education
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    • v.13 no.2
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    • pp.59-70
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    • 2010
  • This study aims to analyze research trend of Web 2.0 use in education and to suggest directions for further studies. Sixty representative studies were selected and analyzed in terms of a developed framework of Web 2.0 based learning environments and an analysis scheme. This scheme is divided into five dimensions: research targets, research themes, types of Web 2.0 tools, learning theories and research methodology. The findings indicate that a majority of the previous studies aimed to share information and reflect thoughts in collaborative contexts through blogs and wikis at universities. Some implications were discussed for further studies.

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Throughput Performance of Slotted ALOHA Communication System with Guard Time and Capture Effect (신호점유 현상과 보호시간을 고려한 슬롯형 알로아 통신 시스템의 성능분석)

  • 이현구;곽경섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.7
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    • pp.989-998
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    • 1993
  • In a bursty user traffic mode, ALOHA random multiple access protocol achieves higher performance than any conventional fixed assignment technique. One of central problems in slotted ALOHA is synchronization. Because of the long propagation delay in satellite mobile communication, packet may be spilt over into adjacent slots and thus guard time may be included between packet intervals. In conventional ALOHA channels, simultaneous transmission by two or more users results in a collision : the unsuccessful packets have to be retransmitted according to some retransmission algorithm. However, in a radio environment, users are often at different distances from the receiver : therefore, their received signals have substantially different power levels. The packet arriving with the highest energy now has a good chance of being detected accurately. Similarly, in some spread-spectrum random access systems, the earliest arriving packet dominates later arriving packets and thus captures the channel. In this paper slotted ALOHA channel with non zero guard time and capture probability is studied. Using the Markovian model, the performance of slotted ALOHA with guard time and capture effects is derived and compared with that of the conventional ALOHA via numerical analysis.

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Access Control for XML Documents Using Extended RBAC (확장된 RBAC를 이용한 XML문서에 대한 접근제어)

  • Kim, Jong-Hun;Ban, Yong-Ho
    • Journal of Korea Multimedia Society
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    • v.8 no.7
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    • pp.869-881
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    • 2005
  • XML(eXtensible Markup Language) has emerged as a prevalent standard for document representation and exchange on the Internet. XML documents contain information of different sensitivity degrees, so that XML Document must selectively shared by user communities. There is thus the need for models and mechanisms enabling the specification and enforcement of access control policies for XML documents. Mechanisms are also required enabling a secure and selective dissemination of documents to users, according to the authorizations which the users have. In this paper, we give an account of access control model and mechanisms, which XML documents can be securely protected in web environments. We make RBAC Based access Control polices to the problem of secure and selective access of XML documents. The proposed model and mechanism guarantee that the secure use for XML documents through definition of authority for element, attribute, link within XML document as well as XML document.

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A Single Re-encryption key based Conditional Proxy Re-Encryption Scheme (조건값의 개수에 독립적인 조건부 프록시 재암호화 기법)

  • Son, Junggab;Oh, Heekuck;Kim, SangJin
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.23 no.2
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    • pp.147-155
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    • 2013
  • Proxy re-encryption scheme has advantage where plaintext does not get exposed during re-encryption process. This scheme is popular for sharing server-saved data in case of cloud computing or mobile office that uses server to save data. Since previous proxy re-encryption schemes can use re-encryption key over and over again, it may abuse re-encryption. To solve this problem, conditional proxy re-encryption scheme was proposed. But, it is computationally expensive generate the same number of re-encryption key with the number of condition values. In this paper, we propose an efficient conditional proxy re-encryption scheme in terms of re-encryption key generation. The proposed scheme uses only encryption and decryption process. Therefore it has advantage to generate one re-encryption key for one person. The proposed scheme is secure against chosen-ciphertext attack.

Hydrogen ion-selective membrane electrodes based on arylamines as neutral carriers (아릴아민계의 중성운반체를 이용한 수소이온선택성 막전극)

  • Jeong, Seong-Suk;Cho, Dong-Hoe;Kim, Jae-Woo;Chung, Koo-Chun;Park, Myon-Yong
    • Analytical Science and Technology
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    • v.9 no.1
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    • pp.78-83
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    • 1996
  • Hydrogen ion-selective membrane electrodes based on tribenzylamine(TBA), tetrabenzylethylenediamine(TBEDA), pentabenzyldiethylenetriamine(PBDETA) as neutral carriers were shown good selectivity and linearity in the range of pH 1~pH 9, pH 2~pH 12, pH 4~pH 12. The pH selectivity of this membrane electrodes have nothing relation with the numbers of unshared electron pair in TBA, TBEDA, PBDETA and were shown a slope of 43.8mV/pH, 46.9mV/pH, 43.6mV/pH respectively. The selectivity coefficients were determined by the separate solution method for alkali(Li+, Na+, K+), alkaline earth metal(Ba2+, Ca2+, Mg2+) and transition metal ions(Mn2+, Co2+, Ni2+, Cu2+, Zn2+). The membrane electrode based on TBEDA appeared the best results as hydrogen ion electrode.

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Development of an Immersive Virtual Reality-Based Bathroom Self-Remodeling System

  • Mi-Young Song
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.4
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    • pp.63-72
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    • 2024
  • The size of the home interior market is growing rapidly as interest in interiors and self-interiors has increased due to the recent rapid increase in single-person households. Most of the Bathroom remodeling is done by requesting an offline interior contractor and then visually checking it in the final completion stage, so it is not easy to re-construct even if the customer is dissatisfied. Therefore, this study developed an immersive virtual reality-based Bathroom self-remodeling system that can visually check space and design from the design stage to the final stage by incorporating VR technology to feel realistic in virtual reality. The bathroom structure may select the basic structure of the predefined bathroom space or freely set the size of the bathroom space. For furniture items, you can choose the washbasin, toilet, bathtub, shower booth that are essential elements of the bathroom and others(mounting rack, trash bin, handle). The tile texture may change the texture of the selected tile at a desired wall position by selecting various textures. In particular,, the texture of the wall tile can be varied by selecting horizontal, vertical and inclined directions at the desired angle according to the needs of the user and the contractor. As a future research project, this system will enable indoor sharing between users who are physically far away in real-time, allowing direct experience in virtual spaces, connection to purchases, and request estimates.

In situ Microfluidic Method for the Generation of Monodisperse Double Emulsions (미세유체를 이용한 단분산성 이중 에멀젼 생성 방법)

  • Hwang, So-Ra;Choi, Chang-Hyung;Kim, Hui-Chan;Kim, In-Ho;Lee, Chang-Soo
    • Polymer(Korea)
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    • v.36 no.2
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    • pp.177-181
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    • 2012
  • This study presents the preparation of double emulsions in a poly(dimethylsiloxane) (PDMS)-based microfluidic device. To improve the wettability of hydrophilic continuous phase onto a hydrophobic PDMS microchannel, the surface was modified with 3-(trimethoxysilyl) propyl methacrylate (TPM) and then sequentially reacted with acrylic acid monomer solution, which produced selective covalent bonding between acrylic acids and methacrylate groups. For the proof of selective surface modification, tolonium chloride solution was used to identify the modified region and we confirmed that the approach was successfully performed. When water containing 0.5% w/w sodium dodecyl sulfate and 1% w/w Span80 with hexadecane were loaded into the selectively modified microfluidic channels, we can produce stable double emulsion. Based on the spreading coefficients, we predict the morphology of double emulsions. Our proposed method efficiently produces monodisperse double emulsions having 48.5 μm(CV:1.6%) core and 65.1 μm (CV:1.6%) shell. Furthermore, the multiple emulsions having different numbers of core were easily prepared by simple control of flow rates.

TouchWiz Evolution

  • Yang, Hui-Cheol
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 2009.11a
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    • pp.46-46
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    • 2009
  • 2007년 본격적으로 시장에 출시된 터치폰은 시장의 관심을 받으며, 휴대전화의 한 영역으로 자리매김하였다. 전세계 휴대전화 시장에서 터치폰이 차지하는 비중은 급속도로 증가하고 있다. 삼성전자는 시장에 후발주자로서 터치폰 시장에 진입하였음에도 불구하고, 2009년 3분기 기준 전세계 터치폰 시장의 23.9% 점유율을 차지하며 1위를 차지하고 있다.터치폰에서의 선전으로 삼성전자는 전세계 휴대전화 판매량의 20.3%를 달성하며 2위 자리를 확고히 하고 있다. 이러한 상승 추세는 지속될 것으로 보이며, 터치폰에서의 성공에는 TouchWiz UX가 중심에 있다고 할 수 있다. 본 세션에서는 TouchWiz UX를 통한 삼성 터치폰의 성공 전략에 대해 소개하고자한다. 우선 TouchWiz UX가 탄생할 수 있었던 배경으로서 당사의 디자인 철학이자 UX 다지인 철학을 간단하게 소개한다. "Creating Emotional Journey"라는 슬로건 아래 "Desire", "Intrigue", "Delight"라는 핵심철학을 공유하고 있다. 다음으로 TouchWiz UX를 성공 시킬 수 있었던 UX 추진 전략을 "Good UX 전략", "브랜드화 전략", "진화 전략", "확산 전략" 으로 나누어 소개한다. 첫째, Good UX 전략에서는 "Simple", "Robust", "Reliable"의 3대 원칙하에 사용성이 높고 감성을 자극하는 UX를 만들기위해 노력하였다. 둘째, 브랜드화 전략에서는 UX를 마케팅에 적극적으로 활용하여 TouchWiz라는 UX 브랜드를 탄생시켰다. 셋째, 진화 전략에서는 TouchWiz 1.0에서 2.0으로 진화하는 과정에서 핵심적인 부분은 유지하면서 발전시켜 나가는 전략을 선택하였다. 넷째, 확산 전략에서는 TouchWiz UX가 각기 다른 OS, Platform, 사업자에 따라 공통화, 차별화를 병행하여 확산하였다. 마지막으로, 내년에 소개될 TouchWiz 3.0에 대해 전략과 키워드를 간단히 소개한다.

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