• 제목/요약/키워드: Compromise Solution

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Comparative analysis of blockchain trilemma

  • Soonduck Yoo
    • International journal of advanced smart convergence
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    • 제12권1호
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    • pp.41-52
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    • 2023
  • The purpose of this study is to review the proposed solutions to the Blockchain trilemma put forward by various research scholars and to draw conclusions by comparing the findings of each study. We found that the models so far developed either compromise scalability, decentralization, or security. The first model compromises decentralization. By partially centralizing the network, transaction processing speed can be improved, but security strength is weakened. Examples of this include Algorand and EOS. Because Algorand randomly selects the node that decides the consensus, the security of Algorand is better than EOS, wherein a designated selector decides. The second model recognizes that scalability causes a delay in speed when transactions are included in a block, reducing the system's efficiency. Compromising scalability makes it possible to increase decentralization. Representative examples include Bitcoin and Ethereum. Bitcoin is more vital than Ethereum in terms of security, but in terms of scalability, Ethereum is superior to Bitcoin. In the third model, information is stored and managed through various procedures at the expense of security. The application case is to weaken security by applying a layer 1 or 2 solution that stores and reroutes information. The expected effect of this study is to provide a new perspective on the trilemma debate and to stimulate interest in continued research into the problem.

Hybrid High-efficiency Synchronous Converter using Si IGBT and SiC MOSFET

  • Il Yang;Woo-Joon Kim;Tuan-Vu Le;Seong-Mi Park;Sung-Jun Park;Ancheng Liu
    • 한국산업융합학회 논문집
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    • 제26권6_1호
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    • pp.967-976
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    • 2023
  • Currently, with the thriving development in the field of solar energy, the widespread adoption of solar grid-connected power conversion systems is rapidly expanding. As the market continues to grow, the efficiency of solar power conversion systems is steadily increasing, while prices are rapidly decreasing. Photovoltaic panels often produce low output voltages, and Boost converters are commonly employed to elevate and stabilize these voltages. They are also utilized for implementing Maximum Power Point Tracking (MPPT), ensuring the full utilization of solar power generation. Recently, synchronous control techniques have been introduced, using controllable switching devices like Si IGBT or SiC MOSFET to replace the diodes in the original circuits. However, this has raised concerns related to costs. This paper offers a compromise solution, considering both the performance and economic factors of the converter. It proposes a hybrid high-efficiency synchronous converter structure that combines Si IGBT and SiC MOSFET. Additionally, the proposed topology has been practically implemented and tested, with results confirming its feasibility and cost-effectiveness.

FUZZY GOAL PROGRAMMING FOR CRASHING ACTIVITIES IN CONSTRUCTION INDUSTRY

  • Vellanki S.S. Kumar;Mir Iqbal Faheem;Eshwar. K;GCS Reddy
    • 국제학술발표논문집
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    • The 2th International Conference on Construction Engineering and Project Management
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    • pp.642-652
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    • 2007
  • Many contracting firms and project managers in the construction industry have started to utilize multi objective optimization methods to handle multiple conflicting goals for completing the project within the stipulated time and budget with required quality and safety. These optimization methods have increased the pressure on decision makers to search for an optimal resources utilization plan that optimizes simultaneously the total project cost, completion time, and crashing cost by considering indirect cost, contractual penalty cost etc., practically charging them in terms of direct cost of the project which is fuzzy in nature. This paper presents a multiple fuzzy goal programming model (MFGP) that supports decision makers in performing the challenging task. The model incorporates the fuzziness which stems from the imprecise aspiration levels attained by the decision maker to these objectives that are quantified through fuzzy linear membership function. The membership values of these objectives are then maximized which forms the fuzzy decision. The problem is solved using LINGO 8 optimization solver and the best compromise solution is identified. Comparison between solutions of MFGP, fuzzy multi objective linear programming (FMOLP) and multiple goal programming (MGP) are also presented. Additionally, an interactive decision making process is developed to enable the decision maker to interact with the system in modifying the fuzzy data and model parameters until a satisfactory solution is obtained. A case study is considered to demonstrate the feasibility of the proposed model for optimization of project network parameters in the construction industry.

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Glass Dissolution Rates From MCC-1 and Flow-Through Tests

  • Jeong, Seung-Young
    • 한국방사성폐기물학회:학술대회논문집
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    • 한국방사성폐기물학회 2004년도 학술논문집
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    • pp.257-258
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    • 2004
  • The dose from radionuclides released from high-level radioactive waste (HLW) glasses as they corrode must be taken into account when assessing the performance of a disposal system. In the performance assessment (PA) calculations conducted for the proposed Yucca Mountain, Nevada, disposal system, the release of radionuclides is conservatively assumed to occur at the same rate the glass matrix dissolves. A simple model was developed to calculate the glass dissolution rate of HLW glasses in these PA calculations [1]. For the PA calculations that were conducted for Site Recommendation, it was necessary to identify ranges of parameter values that bounded the dissolution rates of the wide range of HLW glass compositions that will be disposed. The values and ranges of the model parameters for the pH and temperature dependencies were extracted from the results of SPFT, static leach tests, and Soxhlet tests available in the literature. Static leach tests were conducted with a range of glass compositions to measure values for the glass composition parameter. The glass dissolution rate depends on temperature, pH, and the compositions of the glass and solution, The dissolution rate is calculated using Eq. 1: $rate{\;}={\;}k_{o}10^{(ph){\eta})}{\cdot}e^{(-Ea/RT)}{\cdot}(1-Q/K){\;}+{\;}k_{long}$ where $k_{0},\;{\eta}$ and Eaare the parameters for glass composition, pH, $\eta$ and temperature dependence, respectively, and R is the gas constant. The term (1-Q/K) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_{0},\;{\eta}\;and\;E_{a}$ are the parameters for glass composition, pH, and temperature dependence, respectively, and R is the gas constant. The term (1-Q/C) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_0$, and Ea are determined under test conditions where the value of Q is maintained near zero, so that the value of the affinity term remains near 1. The dissolution rate under conditions in which the value of the affinity term is near 1 is referred to as the forward rate. This is the highest dissolution rate that can occur at a particular pH and temperature. The value of the parameter K is determined from experiments in which the value of the ion activity product approaches the value of K. This results in a decrease in the value of the affinity term and the dissolution rate. The highly dilute solutions required to measure the forward rate and extract values for $k_0$, $\eta$, and Ea can be maintained by conducting dynamic tests in which the test solution is removed from the reaction cell and replaced with fresh solution. In the single-pass flow-through (PFT) test method, this is done by continuously pumping the test solution through the reaction cell. Alternatively, static tests can be conducted with sufficient solution volume that the solution concentrations of dissolved glass components do not increase significantly during the test. Both the SPFT and static tests can ve conducted for a wide range of pH values and temperatures. Both static and SPFt tests have short-comings. the SPFT test requires analysis of several solutions (typically 6-10) at each of several flow rates to determine the glass dissolution rate at each pH and temperature. As will be shown, the rate measured in an SPFt test depends on the solution flow rate. The solutions in static tests will eventually become concentrated enough to affect the dissolution rate. In both the SPFt and static test methods. a compromise is required between the need to minimize the effects of dissolved components on the dissolution rate and the need to attain solution concentrations that are high enough to analyze. In the paper, we compare the results of static leach tests and SPFT tests conducted with simple 5-component glass to confirm the equivalence of SPFT tests and static tests conducted with pH buffer solutions. Tests were conducted over the range pH values that are most relevant for waste glass disssolution in a disposal system. The glass and temperature used in the tests were selected to allow direct comparison with SPFT tests conducted previously. The ability to measure parameter values with more than one test method and an understanding of how the rate measured in each test is affected by various test parameters provides added confidence to the measured values. The dissolution rate of a simple 5-component glass was measured at pH values of 6.2, 8.3, and 9.6 and $70^{\circ}C$ using static tests and single-pass flow-through (SPFT) tests. Similar rates were measured with the two methods. However, the measured rates are about 10X higher than the rates measured previously for a glass having the same composition using an SPFT test method. Differences are attributed to effects of the solution flow rate on the glass dissolution reate and how the specific surface area of crushed glass is estimated. This comparison indicates the need to standardize the SPFT test procedure.

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호흡 곤란을 유발한 미분화 갑상선암에서 기관 스텐트 삽입 1예 (A Case of Tracheal Stent Insertion in Airway Compromise Resulting from Anaplastic Thyroid Cancer)

  • 남우주;김소연;김태환;이상혁
    • 대한두경부종양학회지
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    • 제33권1호
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    • pp.47-52
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    • 2017
  • Anaplastic thyroid cancer is a rare disease entity consist 2% of whole thyroid cancer but once diagnosed, it is too fatal to survive. Airway obstruction is a leading cause of death in anaplastic thyroid cancer, which may be caused by both vocal cord palsy, mass effect of the cancer or direct invasion of the cancer itself to the tracheal lumen. Tracheal stent insertion can be a solution for airway compromised cases where surgical excision cannot be performed. The advantage is that the airway problem can be solved without invasive procedure. In this case, we tried expandable tracheal stent insertion for 66 years-old man with anaplastic cancer who visited ER for small amount of hemoptysis and dyspnea. There was severe tracheal narrowing and deviation due to the anaplastic thyroid cancer, ECMO (Extra Corporal Membrane Oxygenation) was used instead of a tracheal intubation for general anesthesia.

작전부대의 인원편성 최적화를 위한 워게임 전투실험 방법에 대한 연구 (A Study on Warfighting Experimentation for Organizing Operational Troops)

  • 이용빈;염봉진
    • 한국군사과학기술학회지
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    • 제14권3호
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    • pp.423-431
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    • 2011
  • Warfighting experimentation is an important process for identifying requirements against changing military environment and for verifying proposed measures for reforming military service. The wargame simulation experiment is regarded as one of the most effective means to warfighting experimentation, and its importance is increasing than ever. On the other hand, the results of wargame experiments could be unreliable due to the uncertainty involved in the experimental procedure. To improve the reliability of the experimental results, systematic experimental procedures and analysis methods must be employed, and the design and analysis of experiments technique can be used effectively for this purpose. In this paper, AWAM, a wargame simulator, is used to optimize the organization of operational troops. The simulation model describes a warfighting situation in which the 'survival rate of our force' and the 'survival rate of the enemy force' are considered as responses, 'the numbers of weapons in the squad' as control factors, and 'the uncontrollable variables of the battlefield' as noise factors. In addition, for the purpose of effective experimentation, the product array approach in which the inner and outer orthogonal arrays are crossed is adopted. Then, the signal-to-noise-ratio for each response and the desirabilities for the means and standard deviations of responses are calculated and used to determine a compromise optimal solution. The experimental procedures and analysis methods developed in this paper can provide guidelines for designing and analyzing wargame simulation experiments for similar warfighting situations.

Growth and Electrochemical Behavior of Poly[Ni(saldMp)] on Carbon Nanotubes as Potential Supercapacitor Materials

  • Zhang, Yakun;Li, Jianling;Kang, Feiyu;Wang, Xindong;Ye, Feng;Yang, Jun
    • Bulletin of the Korean Chemical Society
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    • 제33권6호
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    • pp.1972-1978
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    • 2012
  • The polymer of (2,2-dimethyl-1,3-propanediaminebis(salicylideneaminato))-nickel(II), Ni(saldMp), was deposited on multi-walled carbon nanotubes (MWCNTs) substrate by the route of potential linear sweep. The nano structures of poly[Ni(saldMp)] have been obtained by adjusting the monomer concentration of 0.1, 0.2, 0.5, 1.0 and 1.5 mmol $L^{-1}$. The poly[Ni(saldMp)] prepared in acetonitrile solution with monomer concentration of 1.0 mmol $L^{-1}$ shows the fastest growth rate. The effects of potential window on charge-discharge efficiency and electrodeposition scan number on capacitance performance were discussed. Poly[Ni(saldMp)] prepared with less electrodeposition scans exhibits higher capacitance, but this goes against the improvement of the whole electrode capacitance. Sample with 8 deposition scans is the best compromise with the geometric specific capacitance 3.53 times as high as that of pure MWCNTs, and 1.24 times for the gravimetric specific capacitance under the test potential window 0.0-1.0 V.

이종 조직판막의 재치환수술 (Replacement of the Xenograft Cardiac Valves)

  • 김종환
    • Journal of Chest Surgery
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    • 제21권4호
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    • pp.619-629
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    • 1988
  • The increasing number of replacement of the substitute cardiac valves were seen in these 2 years. Out of a total 1,408 patients with cardiac valve replacement, 54 required replacement of the substitute valves. Fifty-nine substitute valves replaced were 43 in mitral, 14 in aortic and 2 in tricuspid positions; and they were 36 Ionescu-Shiley, 15 Hancock and 3 Angell-Shiley bioprosthetic valves and 3 St. Jude Medical and 2 Bjork-Shiley prosthetic valves. Primary tissue failure was the most frequent reason of replacement[38 patients] followed by paravalvular leak[9 patients], prosthetic valve endocarditis[6 patients] and valve thrombosis[1 patient] in order. The most pronounced pathology of the failed xenograft valves seen in the primary tissue failure group was calcification and fixation of the cusps with or without tear and defect of the cuspal tissue. The operative mortality rate was 7.4%. Fifty early survivors were followed up for a total of 82.6 patient-years and there was no late death. Actuarial survival rate was 92.3*3.8% at 6 years after surgery. Although the definite tendency toward early and accelerated degeneration of the xenograft valves has been seen in patients younger than 20 to 25 years of age, no strict age limit from where the tissue failure slows down could be determined. The requirement of the ideal substitute valves would be the durability of the recently developed mechanical prostheses armed with the low thrombogenicity of the bioprostheses. At the present time, the need of compromise in selection between less thrombogenic bioprosthetic and more durable mechanical valves should be stressed. The difficulty in choice is yet important in patients of middle age and children where the use of homograft valves may be one of the solution despite of certain limitations from sociomedical reasons.

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가시광 통신 채널의 취약성 및 공격 방법 (Vulnerabilities and Attack Methods in Visible Light Communications Channel)

  • 박소현;주소영;이일구
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2021년도 추계학술대회
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    • pp.469-471
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    • 2021
  • 무선 통신 기술이 방대한 양의 데이터를 빠른 속도로 높은 정확도와 안전성을 보장하여 전송하는 방식에 초점을 맞추어 발전하면서 기존의 무선 주파수(RF, Radio Frequency)를 이용한 무선 통신 기술의 대안으로 가시광 통신(VLC, Visible Light Communication) 기술의 연구개발이 가속화되었다. RF 무선 통신의 전파 스펙트럼이 더욱 혼잡해지고, 대역폭에 대한 수요가 지속적으로 증가함에 따라 규제되지 않은 대역폭을 사용할 수 있는 VLC가 해결책으로 제시되고 있다. 하지만, VLC 채널은 LOS(Line of Sight) 전파 특성으로 중간자 공격(MITM, Man-In-The-Middle)에 취약하고 도청과 재밍 공격에 쉽게 노출될 수 있다는 문제점이 있다. 이러한 VLC 채널에 대한 공격은 통신 링크 및 데이터의 기밀성, 무결성 및 가용성을 훼손하고, 데이터 재전송률이 높아져 스루풋이 감소하고 전력 소모량이 증가하여 데이터 전송 효율성이 낮아지는 문제점이 있다. 본 연구에서는 취약한 VLC 채널을 모델링하여 악의적인 재머에 의한 공격 영향과 통신 취약성을 분석한다.

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개성공단에서의 남북상사중재위원회 구성.운영에 관한 연구 (A Study on the Organization and Operation of the Inter-Korean Commercial Arbitration Committee in Gaeseong Complex)

  • 김광수
    • 한국중재학회지:중재연구
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    • 제24권2호
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    • pp.3-31
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    • 2014
  • As all aspects of international activity have kept growing in good transaction, transnational investments, joint ventures, and the licensing of intellectual property, it is inevitable for disputes to increase across national frontiers. International disputes can be settled by arbitration and ADR. In the situation presented in the paper, any dispute shall be finalized by arbitration and conciliation in the Gaeseong Industrial Complex. Inter-Korean Commercial Arbitration in the Gaeseong Industrial Complex has become the principal method of resolving disputes in trade, commerce, and investment in accordance with the "Agreement on South-North Commercial Dispute Settlement Procedures," "Agreement on Organization and Operation of Inter-Korean Commercial Arbitration Committee," and the Annexed Agreement on "Organization and Operation of Inter-Korean Commercial Arbitration Committee" (2013). But the follow-up measures of the said agreements have not been fulfilled. Some prerequisite measures of the Inter-Korean commercial arbitration must be satisfied. In order to proceed with arbitration and conciliation in the Gaeseong Industrial Complex, we need to ask the following: Does the status of an arbitrational matter? Should an agreement to arbitrate contain a choice of law clause? Should one provide for one arbitrator or three? How should the arbitrators be selected? What is the relation between party-appointed arbitrators and the presiding arbitrator (neutral arbitrator)? Do arbitrators compromise more than the litigation? Can conciliation be combined with arbitration? To execute the enactment of arbitration regulations, the contents of the Arbitration Rules of the Korean Commercial Arbitration Board (South) and the Korea International Trade Arbitration Committee (North), together with the Korean Arbitration Act and External Arbitration Act of North Korea and the UNCITRAL Model Arbitration Law and UNCITRAL l Arbitration Rules are reflected in the Rules. There are many aspects of the Inter-Korean Commercial Arbitration. It is essential to understand key elements; namely, the arbitration agreement, appointment of arbitrator, arbitral proceeding and arbitral award, and enforcement and setting aside of arbitral award. This research deals with five chapters. Chapter 1 provides the introduction. Chapter 2 deals with trade volume between South and North Korea and the kinds of dispute in Gaeseong. Chapter 3 addresses contents and follow-up measures of the agreement on the "South-North Commercial Dispute Settlement Procedures," "Agreement on Organization and Operation of Inter-Korean Commercial Arbitration Committee," and the Annexed Agreement on "Organization and Operation of Inter-Korean Commercial Arbitration Committee" (2013). Chapter 4 features the problems and tasks of the pertinent agreements. Chapter 5 gives the conclusion. Enabling parties to find an amicable solution to the dispute in the Gaeseong Industrial Complex can lead to a useful and appropriate framework either through direct negotiation or by resorting to conciliation or mediation in accordance with pertinent agreements and follow-up measures contained in the agreements.

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