• Title/Summary/Keyword: Variable transformation

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Development of High Precision Fastening torque performance Nut-runner System (고정밀 체결토크 성능 너트런너 시스템 개발)

  • Kim, Youn-Hyun;Kim, Sol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.35-42
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    • 2019
  • Nut fasteners that require ultra-precise control are required in the overall manufacturing industry including electronic products that are currently developing with the automobile industry. Important performance factors when tightening nuts include loosening due to insufficient fastening force, breakage due to excessive fastening, Tightening torque and angle are required to maintain and improve the assembling quality and ensure the life of the product. Nut fasteners, which are now marketed under the name Nut Runner, require high torque and precision torque control, precision angle control, and high speed operation for increased production, and are required for sophisticated torque control dedicated to high output BLDC motors and nut fasteners. It is demanded to develop a high-precision torque control driver and a high-speed, low-speed, high-response precision speed control system, but it does not satisfy the high precision, high torque and high speed operation characteristics required by customers. Therefore, in this paper, we propose a control technique of BLDC motor variable speed control and nut runner based on vector control and torque control based on coordinate transformation of d axis and q axis that can realize low vibration and low noise even at accurate tightening torque and high speed rotation. The performance results were analyzed to confirm that the proposed control satisfies the nut runner performance. In addition, it is confirmed that the pattern is programmed by One-Stage operation clamping method and it is tightened to the target torque exactly after 10,000 [rpm] high speed operation. The problem of tightening torque detection by torque ripple is also solved by using disturbance observer Respectively.

Evaluating the Efficiency of Personal Information Protection Activities in a Private Company: Using Stochastic Frontier Analysis (개인정보처리자의 개인정보보호 활동 효율성 분석: 확률변경분석을 활용하여)

  • Jang, Chul-Ho;Cha, Yun-Ho;Yang, Hyo-Jin
    • Informatization Policy
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    • v.28 no.4
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    • pp.76-92
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    • 2021
  • The value of personal information is increasing with the digital transformation of the 4th Industrial Revolution. The purpose of this study is to analyze the efficiency of personal information protection efforts of 2,000 private companies. It uses a stochastic frontier approach (SFA), a parametric estimation method that measures the absolute efficiency of protective activities. In particular, the personal information activity index is used as an output variable for efficiency analysis, with the personal information protection budget and number of personnel utilized as input variables. As a result of the analysis, efficiency is found to range from a minimum of 0.466 to a maximum of 0.949, and overall average efficiency is 0.818 (81.8%). The main causes of inefficiency include non-fulfillment of personal information management measures, lack of system for promoting personal information protection education, and non-fulfillment of obligations related to CCTV. Policy support is needed to implement safety measures and perform personal information encryption, especially customized support for small and medium-sized enterprises.

Synthesis, Characterization and Ammonia Decomposition Reaction Activity of Vanadium Oxynitride Obtained from the Reduction/Nitridation of Vanadium Oxide (바나디움 산화물의 환원 및 질화반응으로부터 얻어진 바나디움 산화질화물의 제조, 특성분석 및 암모니아 분해반응에서의 촉매 활성)

  • Yun, Kyung Hee;Shin, Chae-Ho
    • Korean Chemical Engineering Research
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    • v.60 no.4
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    • pp.620-629
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    • 2022
  • By varying various experimental conditions such as heating rate, molar hourly space velocity (MHSV), and nitridation reaction temperature, vanadium oxynitride was prepared through temperature programmed reduction/nitridation reaction (TPRN) of vanadium pentoxide and ammonia, and characterization were performed. In order to investigate the physico-chemical properties of the prepared catalyst, N2 adsorption-desorption analysis, X-ray diffraction analysis (XRD), hydrogen temperature programmed reduction (H2-TPR), temperature programmed oxidation (TPO), ammonia temperature programmed desorption (NH3-TPD), transmission electron microscopy (TEM) was performed. Transformation of V2O5 with 5 m2 g-1 low specific surface area by reduction at 340 ℃ to V2O3 showed a high specific surface area value of 115 m2 g-1 by micropore formation. As the nitridation temperature increased beyond that, the specific surface area continued to decrease due to sintering. The nitridation reaction variable that had the greatest influence on the specific surface area was the reaction temperature, and the x + y value of VNxOy of a single phase approached from 1.5 to 1.0 as the nitridation reaction temperature increased. At a high reaction temperature of 680 ℃, the cubic lattice constant a was VN. close to the value. At 680 ℃, the highest nitridation temperature among the experimental conditions, the ammonia conversion rate was 93%, and no deactivation was observed.

Annotation-guided Code Partitioning Compiler for Homomorphic Encryption Program (지시문을 활용한 동형암호 프로그램 코드 분할 컴파일러)

  • Dongkwan Kim;Yongwoo Lee;Seonyoung Cheon;Heelim Choi;Jaeho Lee;Hoyun Youm;Hanjun Kim
    • The Transactions of the Korea Information Processing Society
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    • v.13 no.7
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    • pp.291-298
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    • 2024
  • Despite its wide application, cloud computing raises privacy leakage concerns because users should send their private data to the cloud. Homomorphic encryption (HE) can resolve the concerns by allowing cloud servers to compute on encrypted data without decryption. However, due to the huge computation overhead of HE, simply executing an entire cloud program with HE causes significant computation. Manually partitioning the program and applying HE only to the partitioned program for the cloud can reduce the computation overhead. However, the manual code partitioning and HE-transformation are time-consuming and error-prone. This work proposes a new homomorphic encryption enabled annotation-guided code partitioning compiler, called Heapa, for privacy preserving cloud computing. Heapa allows programmers to annotate a program about the code region for cloud computing. Then, Heapa analyzes the annotated program, makes a partition plan with a variable list that requires communication and encryption, and generates a homomorphic encryptionenabled partitioned programs. Moreover, Heapa provides not only two region-level partitioning annotations, but also two instruction-level annotations, thus enabling a fine-grained partitioning and achieving better performance. For six machine learning and deep learning applications, Heapa achieves a 3.61 times geomean performance speedup compared to the non-partitioned cloud computing scheme.

The Empirical Study on the Effects of the Team Empowerment caused by the Team-Based Organizational Structure in KBS (팀제가 팀 임파워먼트에 미치는 영향에 관한 연구;KBS 팀제를 중심으로)

  • Ahn, Dong-Su;Kim, Hong
    • 한국벤처창업학회:학술대회논문집
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    • 2006.04a
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    • pp.167-201
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    • 2006
  • Korean corporations are transforming their vertical operational structure to a team-based structure to compete in the rapidly changing environment and for improved performance. However, a high percentage of the respondents in KBS said that despite the appearance of the present team structure, the organization operates much like a vertically-structured organization. This result can be attributed to the lack of study and implementation toward the goal of empowerment, the key variable for the success of the team-based structure. This study aims to provide policy suggestions on how to implement the process of empowerment, by investigating the conditions that hinder the process and the attitude of the KBS employees. For the cross-sectional study, this thesis examined the domestic and international references, conducted a survey of KBS employees, personal interviews and made direct observations. Approximately 1,200 copies of the Questionnaire were distributed and 474 were completed and returned. The analysis used SPSS 12.0 software to process the data collected from 460 respondents. For the longitudinal-study, six categories that were common to this study and "The Report of the Findings of KBS Employees' View of the Team Structure" were selected. The comparative study analyzed the changes in a ten-month period. The survey findings showed a decrease of 24.2%p in the number of responses expressing negative views of the team structure and a decrease of 1.29%p in the number of positive responses. The findings indicated a positive transformation illustrating employees' improved understanding and approval of the team structure. However, KBS must address the issue on an ongoing basis. It has been proven that the employee empowerment increases the productivity of the individual and the group. In order to boost the level of empowerment, the management must exercise new, innovative leadership and build trust between the managers and the employees first. Additional workload as a result of shirking at work places was prevalent throughout all divisions and ranks, according to the survey data. This outcome leads to the conclusion that the workload is not evenly distributed or shared. And the data also showed the employees do not trust the assessment and rewards system. More attention and consideration must be paid to the team size and job allocation in order to address this matter; the present assessment and rewards system need to be complemented. The type of leadership varies depending on the characteristics of the organization's structure and employees' disposition. KBS must develop and reform its own management, leadership style to suit the characteristics of individual teams. Finally, for a soft-landing of KBS team structure, in-house training and education are necessary.

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Development of A Material Flow Model for Predicting Nano-TiO2 Particles Removal Efficiency in a WWTP (하수처리장 내 나노 TiO2 입자 제거효율 예측을 위한 물질흐름모델 개발)

  • Ban, Min Jeong;Lee, Dong Hoon;Shin, Sangwook;Lee, Byung-Tae;Hwang, Yu Sik;Kim, Keugtae;Kang, Joo-Hyon
    • Journal of Wetlands Research
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    • v.24 no.4
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    • pp.345-353
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    • 2022
  • A wastewater treatment plant (WWTP) is a major gateway for the engineered nano-particles (ENPs) entering the water bodies. However existing studies have reported that many WWTPs exceed the No Observed Effective Concentration (NOEC) for ENPs in the effluent and thus they need to be designed or operated to more effectively control ENPs. Understanding and predicting ENPs behaviors in the unit and \the whole process of a WWTP should be the key first step to develop strategies for controlling ENPs using a WWTP. This study aims to provide a modeling tool for predicting behaviors and removal efficiencies of ENPs in a WWTP associated with process characteristics and major operating conditions. In the developed model, four unit processes for water treatment (primary clarifier, bioreactor, secondary clarifier, and tertiary treatment unit) were considered. Additionally the model simulates the sludge treatment system as a single process that integrates multiple unit processes including thickeners, digesters, and dewatering units. The simulated ENP was nano-sized TiO2, (nano-TiO2) assuming that its behavior in a WWTP is dominated by the attachment with suspendid solids (SS), while dissolution and transformation are insignificant. The attachment mechanism of nano-TiO2 to SS was incorporated into the model equations using the apparent solid-liquid partition coefficient (Kd) under the equilibrium assumption between solid and liquid phase, and a steady state condition of nano-TiO2 was assumed. Furthermore, an MS Excel-based user interface was developed to provide user-friendly environment for the nano-TiO2 removal efficiency calculations. Using the developed model, a preliminary simulation was conducted to examine how the solid retention time (SRT), a major operating variable affects the removal efficiency of nano-TiO2 particles in a WWTP.

Meta-analysis on the Effect of Startup Support Policies to Startup Performance (창업지원정책이 창업성과에 미치는 영향에 관한 메타분석)

  • Kim, Sun Chic;Jeon, Byung Hoon;Yun, Sung Im
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.6
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    • pp.95-114
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    • 2020
  • This paper, a meta-analysis of the effect of the start-up support policy on the start-up performance was conducted to examine the effect of the start-up support policy on the start-up performance of beneficiary companies and to provide theoretical and practical implications to support organizations and practitioners. To this end, 35 papers containing the correlation coefficient, which is a positive statistical value, were selected from the previous studies in academic journals and dissertations published in Korea from 2007 to 2020. In the preceding study of the start-up support policy, the independent variables include funding, education support, facility/equipment support, network support, mentoring support, consulting support, marketing support, management support, technical support, manpower support, and finance as a dependent variable. The effect size of the impact on aptitude and non-financial performance was reviewed. The pattern of the effect size was presented as a forest plot for easy visual understanding, and outliers were verified through sensitivity analysis for small-study-effect data with publication convenience. As a result of analyzing the effect size of the government-supported policy, it was verified that the effect size was generally medium or higher, affecting the entrepreneurial performance. Among the independent variables, the factor that has the greatest effect on startup performance is manpower support, followed by technical support, marketing support, management support, facility/equipment support, education support, mentoring support, funding, network support, and consulting support. It was analyzed that the effect size was large in order. As the 「Small and Medium Business Startup Support Act」 was recently reorganized from the manufacturing industry to digital transformation and smartization on October 8, 2020, the start-up support policy should consider the start-up stage and verify the priorities to organize the budget.

The Effect of Mentoring on the Mentor's Job Satisfaction: Mediating Effects of Personal Learning and Self-efficacy (멘토링이 멘토의 직무만족도에 미치는 영향: 개인학습 및 자기효능감의 매개효과)

  • Lee, In Hong;Dong, Hak Lim
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.3
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    • pp.157-172
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    • 2023
  • The recent Fourth Industrial Revolution is accelerating changes due to digital transformation. According to this trend, the existing start-up paradigm is changing, and new business models based on new technologies and creative ideas are emerging. In addition, the diversity of mentoring relationships and environments such as online mentoring, reverse mentoring, group mentoring, and multiple mentoring is also increasing. However, most mentors in their 50s and 60s, who are mainly active in the start-up field, have been able to help mentees a lot based on their own experience and expertise, but they are having difficulty responding to the changing environment due to a lack of understanding and experience of new technologies and environments. To cope with these changes well, mentors must constantly study, acquire and apply the latest technologies to improve their understanding of new technologies and the environment. In addition, it is necessary to have an understanding and respect for the diversity of mentoring relationships and environments, and to maximize the effectiveness of mentoring by actively utilizing them. Therefore, mentors should recognize that they directly affect the growth and development of mentees, constantly acquire new knowledge and skills to maintain and develop expertise, and actively deliver their knowledge and experiences to mentees. Therefore, in this study, was tried to empirically analyze the relationship between mentoring's influence on mentor's job satisfaction through mentor's personal learning and self-efficacy. The results of the empirical analysis were as follows. Among the functions of mentoring, career function and role modeling were found to have a positive effect on both personal learning and self-efficacy, which are parameters, and job satisfaction, which is a dependent variable. On the other hand, psychological and social functions have a positive effect on personal learning, but they do not have an effect on self-efficacy and job satisfaction. In addition, as a result of analyzing the mediating effect, all mediating effects were confirmed for career functions, and only the mediating effect of self-efficacy was confirmed for role modeling. Through this study, mentoring is an important factor in promoting job satisfaction, personal learning and self-efficacy, and this study can be said to be academically and practically meaningful in that it confirmed personal learning and self-efficacy as factors that increase mentor's job satisfaction, and the focus of mentoring research was shifted from mentee to mentor to study the impact of mentoring on mentors.

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An Analysis on the Conditions for Successful Economic Sanctions on North Korea : Focusing on the Maritime Aspects of Economic Sanctions (대북경제제재의 효과성과 미래 발전 방향에 대한 고찰: 해상대북제재를 중심으로)

  • Kim, Sang-Hoon
    • Strategy21
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    • s.46
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    • pp.239-276
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    • 2020
  • The failure of early economic sanctions aimed at hurting the overall economies of targeted states called for a more sophisticated design of economic sanctions. This paved way for the advent of 'smart sanctions,' which target the supporters of the regime instead of the public mass. Despite controversies over the effectiveness of economic sanctions as a coercive tool to change the behavior of a targeted state, the transformation from 'comprehensive sanctions' to 'smart sanctions' is gaining the status of a legitimate method to impose punishment on states that do not conform to international norms, the nonproliferation of weapons of mass destruction in this particular context of the paper. The five permanent members of the United Nations Security Council proved that it can come to an accord on imposing economic sanctions over adopting resolutions on waging military war with targeted states. The North Korean nuclear issue has been the biggest security threat to countries in the region, even for China out of fear that further developments of nuclear weapons in North Korea might lead to a 'domino-effect,' leading to nuclear proliferation in the Northeast Asia region. Economic sanctions had been adopted by the UNSC as early as 2006 after the first North Korean nuclear test and has continually strengthened sanctions measures at each stage of North Korean weapons development. While dubious of the effectiveness of early sanctions on North Korea, recent sanctions that limit North Korea's exports of coal and imports of oil seem to have an impact on the regime, inducing Kim Jong-un to commit to peaceful talks since 2018. The purpose of this paper is to add a variable to the factors determining the success of economic sanctions on North Korea: preventing North Korea's evasion efforts by conducting illegal transshipments at sea. I first analyze the cause of recent success in the economic sanctions that led Kim Jong-un to engage in talks and add the maritime element to the argument. There are three conditions for the success of the sanctions regime, and they are: (1) smart sanctions, targeting commodities and support groups (elites) vital to regime survival., (2) China's faithful participation in the sanctions regime, and finally, (3) preventing North Korea's maritime evasion efforts.