유압장치용 전기모터 회전속도 제어시스템의 특성 비교

정헌술(Heon-Sul Jeong),정승욱(Seung-Wook Jeong) 유공압건설기계학회 2009 유공압건설기계학회 학술대회논문집 Vol.2009 No.11

Hydraulic systems are widely used as a power transfer and/or power control system due to its flexibility, controllability, accuracy and high power density. Valve controlled and/or pump controlled systems are normally was adopted as a control device, but nowadays motor controlled systems are emerging as new energy-efficient hydraulic control systems. In this paper the motor controlled system for the cylinder position control of a counter balance circuit is investigated by using AMESim simulation study. And position control experiments was carried out verifying the possibility and efficiency of the motor controlled system.

연구논문 : 통제제도와 조직성과간의 관계에서 조직학습의 역할

이상완 ( Sang Wan Lee ),신성호 ( Sung Ho Shin ),김순기 ( Soon Kee Kim ) 한국회계학회 2012 회계저널 Vol.21 No.5

최근의 기업환경은 정보기술의 발전과 시장의 글로벌화에 따라 급격하게 변화하고 있다. 이런환경 하에서 기업들이 경쟁력을 갖추고 장기적으로 성장하기 위해서는 MCS를 정교하게 구축하고 활용해야 할 것이다. MCS는 다양한 통제시스템으로 구성되어 있다(Otley 1980). 과거 선행연구들은 대부분 진단적 통제를 중심으로 연구되었으며, 최근에는 진단적 통제와 함께 상호작용적 통제의 중요성이 강조되고 있다. 그러나 선행연구들에는 신념시스템과 경계시스템에 대한 고려를 거의 찾아 볼 수 없다. MCS의 이용과 조직성과에 미치는 영향에 관한 실증연구들의 결과를 종합해 보면 일관된 결론을 내리기가 쉽지 않다. 대부분의 선행연구들은 성과측정지표의 이용과같은 하나의 통제시스템에 초점을 두어 연구를 진행해왔으며, 진단적 통제와 상호작용적 통제의 측정 방법에도 차이가 존재하였다. 또한 MCS의 특징에 따라 이에 적합한 조직학습의 유형이 달라 질 수 있는데 대부분의 선행연구들은 단일고리학습과 이중고리학습과 같은 상이한 조직학습에 대한 고려가 부족하였다. 본 연구의 목적은 제조기업을 대상으로 통제제도(신념시스템, 경계시스템, 진단적 통제, 상호작용적 통제)의 선행변수로 환경불확실성을 고려하고 통제제도의 후행변수로 조직학습(단일고리학습, 이중고리학습)과 조직성과를 고려하여 이들간의 관계에 대해 보다 나은 이해를 제공하는 데 있다. 이를 위해 2010년 매출액을 기준으로 국내 300대 제조기업을 대상으로 설문조사를 통해 자료를 수집하여 분석을 수행하였다. 이 연구의 결과 및 시사점을 요약하면 다음과 같다. 첫째, 기업은 환경불확실성을 극복하기 위해 조직의 가치, 목적 그리고 조직이 나아가야 할 방향 등을 조직구성원들에게 제공해주는 신념시스템을 강조하는 것으로 나타났다. 둘째, 경영자들은 환경불확실성 하에서 조직성과를 개선시키기 위해 하나의 통제시스템만으로는 한계가 있을 것이며, 신념시스템, 경계시스템, 진단적 통제, 그리고 상호작용적 통제의 보완적 관계를 고려하여 더 정교하게 사용해야 한다. 경계시스템, 진단적 통제, 그리고 상호작용적 통제는 신념시스템을 보완하며, 궁극적으로 조직성과를 개선시키는 것으로 나타났다. 셋째, 조직구성원들의 행동을 제약하는 부정적인 방법인 경계시스템과 진단적 통제의 강조 보다는 동기부여와 의사소통을 촉진하는 긍정적인방법인 신념시스템과 상호작용적 통제의 강조가 조직학습을 더 강화시키는 것으로 나타났다. 따라서 기업은 불확실한 경영환경 속에서 조직성과를 개선시키기 위해 단일고리학습보다 이중고리학습을 강화시켜야 한다. 즉 경영자들은 MCS의 구축목적을 달성하기 위해 이중고리학습의 활용을 보다 적극적으로 고려해야 할 것이다. 마지막으로 신념시스템과 상호작용적 통제는 이중고리 학습을 강화시키고, 이중고리학습은 조직성과를 개선시키고 있음을 보여주었다. Recent business environment is undergoing rapid changes due to the advancement of the information technology and the globalization of market. In such business environment, many business enterprises need to build and utilize complicated management control systems(MCS) in order to improve competitiveness and ensure long-term growth. MCS is a compound system consisting of variety of control systems(Otley 1980). However, there has been almost no studies that also considered beliefs system and boundary system. Review of empirical studies on the use of MCS and its effect on organizational performance do not allow to easily draw one consistent general conclusion. Many past studies were conducted with special focus on only one control such as the use of performance measures and employed different measures of the construct such as diagnostic controls and interactive controls. Additionally organizational learning could be further classified into single loop learning and double loop learning and appropriate type of organizational learning may differ depending on the characteristics of MCS. The purpose of this study is to consider environmental uncertainties such as the antecedent variable of MCS(beliefs system, boundary system, diagnostic controls and interactive controls), organizational learning(single loop learning and double loop learning) and organizational performance as consequence variables of MCS and to present better understanding of their relationships using manufacturing companies as subjects. A survey was conducted using a questionnaire on 300 manufacturing companies in Korea selected based on annual sales for the year 2010 and collected data were analyzed. The results and suggestions of the study can be summarized as follows: First, the results showed that, in order to overcome the uncertainties of the business environment, emphasis must be made on beliefs system for communication on the values, purpose and future direction of organization to the members of organization and for motivation of the members of organization for exploration, creation, and commission. Second, there is a limitation of implementing MCS alone to improve organizational performance under the uncertainties of environment and use of complicated system would be necessary taking into account the complementary relation between beliefs system, boundary system, diagnostic controls and interactive controls. The results suggested that boundary system, diagnostic controls and interactive controls can complement beliefs system and can eventually lead to the improvement of organizational performance. Third, the results showed that emphasis on beliefs system and interactive controls, which are positive methods that facilitate motivation and communication, can improve organizational learning more effectively than the emphasis on boundary system and diagnostic controls, which are negative methods that restrict the activities of the members of the organization. Companies would need to promote double loop learning instead of single loop learning if it is to improve organizational performance in environmental uncertainties. The results also showed that boundary system and interactive controls improve double loop learning and double loop learning, in turn, improves organizational performance.

도로공사 중 발견된 동굴에 대한 교량적용 사례

부상필(Boo, Sangpil),문경태(Moon, Kyoungtae),박상렬(Park, Sangyeol) 대한토목학회 2020 대한토목학회 학술대회 Vol.2020 No.10

제주도에는 화산활동에 의해 형성된 용암동굴이 지하 곳곳에 분포하고 있다. 본 사례에서는 도로공사 중 발견된 용암동굴의 보존을 위해 문화재청의 진동기준을 만족하도록, 공사중 장비사용에 의한 진동을 측정하였다. 공사완료 후 차량하중에 의한 동굴의 안정성을 평가하기 위하여 토공(성토) 시공시 및 교량 적용시에 대한 동적해석을 실시하여 진동치를 예측하였다. 본 사례를 통하여 향후 동굴이 발견되는 경우에 동굴의 안정성과 경제적인 공법을 적용할 수 있는 기초자료로 제공하고자 한다.

스마트 컨트랙트 기반의 산업제어시스템 접근 제어 메커니즘

조민정,이창훈 한국정보보호학회 2019 정보보호학회논문지 Vol.29 No.3

산업제어시스템은 센서, 액추에이터 등의 다양한 물리적인 장치들로 구성된다. 과거에 미국에서 발생했던 상수도시설 원격 접속 사고, 전력 제어시스템 감염 등 대규모 피해를 가져온 보안 사고는 산업제어시스템 접근 제어의 취약점으로 인해 발생했다. 물리적 장치에 대한 접근제어는 신뢰할 수 있는 시스템을 통해 이뤄져야한다. 그러나 폐쇄망으로 구성된 산업제어시스템 내부에 단일 접근 제어 시스템을 구축하는 것은 신뢰성을 보장받을 수 없다. 또 단일 접근제어 시스템은 장애나 사고 발생시 접근 제어 시스템이 작동 불가능해지므로 다른 접근 제어 방법이나 시스템이 필요하다. 본 논문에서는 신뢰성과 안정적인 운영을 제공하기 위해 운영 계층에 블록체인을 이용하고, 스마트 컨트랙트 배포를 통한 접근제어 메커니즘을 제안한다. 또한, 무결성, 기밀성보다 가용성이 우선시 되는 산업제어시스템을 고려하여 각 산업 환경에 맞게 소모할 컴퓨팅 자원을 설정할 수 있도록 신뢰 점수를 이용했다. 본 논문에서 제안하는 시스템은 기 제안된 블록체인 기반의 접근제어 시스템과 달리 현재 운영중인 산업제어시스템의 특성에 맞게 구성했다. Industrial control systems consist of various physical devices such as sensors, actuators. Security Infringement such aswaterworks facilities Remote Access Infringement and power control systems Infection have been occured by vulnerability ofAccess Control. Access control to physical devices must be fulfilled with a reliable system. However, Having a singleaccess control system inside company can not guarantee reliability. In addition, when single access control is struggled witherror or infringement, access control system is totally unavailable. so system requires a additional access control method orsystem. In this paper, we proposed access control mechanism for reliable and stable operation using blockchain and smartcontract. Proposed Mechanism using trust score to consider resources to be consumed depending on each industrialenvironment in consideration of the industrial control system where availability is more important than integrity andconfidentiality. Unlike other blockchain-based access control system, proposed system is designed for the currently operatingindustrial control system.

The integrated monitoring and control system for the combined cycle power plant

Bong-Kuk Lee,Yong-Hak Shin 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

In this paper, the open and standardized integrated monitoring and control system for the combined cycle power plant was developed and verified. The developed integrated monitoring and control system is monitoring and controlling mainly for the boiler called HRSG(Heat recovery steam generator) and BOP(Balance of plant) and Turbine in the thermal power plant. There were various operating modes frequent start-up and shut-down operations for operating the thermal power plant. Accordingly, the control for the various operating modes and the advanced control for the critical equipments was achieved and developed for the integrated monitoring and control system. As a advanced control algorithm, we adopted a MPC(Model predictive controller) MIMO control method. For the integrated monitoring and control system we developed the standardized and open interface APIs(Application program interface) to connect to other system efficiently and the function of web monitoring system to manage the remote monitoring and real time historical system. The developed system was verified in the real power plant environment.

ERP시스템 정보의 전략적 특성 및 거래비용 특성과 경영통제시스템 간의 적합성이 경영성과에 미치는 영향

이은아,송신근 韓國公認會計士會 2008 회계·세무와 감사 연구 Vol.48 No.-

The major aim of this research is to analyze how characteristics of information provided by ERP systems can affect Management Control Systems and analyze how the fit between these two systems can affect business performances. Characteristics in information of ERP systems consist of the strategic importance of information, the firm-specificity of information, the uncertainty of information, and the spread of information. Also, the types of management control systems are behavior control, non-traditional result control and traditional result control. In addition, the dependent variables related to the fit between two systems are divided into the financial and non-financial performances. The following are the results of this research; First, behavior control is significantly affected by the strategic importance of information. The firm-specificity of information partially affects and the spread of information affects non-traditional result control. Second, the fit between characteristics of information and behavior control, and also traditional result control has positive influence on business performance. Third, The result shows that the effect of the interaction between the information characteristics of ERP systems and behavior control improve significantly on the business performances. The effect of the interaction between the strategic importance of information and the spread of information and non-traditional result control has positive influence on the business performances. And the effect of the interaction between the information characteristics of ERP systems and traditional result control bring the significance on the business performances partially. These results show that by choosing appropriate management control types which make full use of each characteristics of information provided by ERP systems, a company can improve business performance which company pursues. Further, it is concluded that when it pursues the improvement of the business performances by using the information characteristics of ERP systems, it is necessary to design strategy and to improve the level of the behavior control of group members. 본 연구는 통합정보시스템으로서의 ERP시스템이 제공하는 정보의 특성 중 전략적 특성과 거래비용 특성이 경영통제시스템의 유형에 어떠한 영향을 미치며, 또한 이들 간의 적합성이 경영성과에 어떠한 영향을 미치는지 분석하고자 하였다. 연구는 증권거래소 상장제조기업의 회계담당자들을 대상으로 설문조사에 의해 이루어졌다. 연구변수로 ERP시스템 정보특성은 정보의 전략적 중요성, 정보 특수성, 정보 정형성 및 정보 확산을 사용하였으며, 경영통제시스템의 유형은 행위통제, 비전통적 결과통제 및 전통적 결과통제를 사용하였고, 경영성과로는 재무적 성과와 비재무적 성과를 사용하였다. 분석결과, 경영통제시스템의 유형에는 ERP시스템 정보 특성 중 정보의 전략적 중요성이 행위통제에, 정보 특수성과 정보 확산이 비전통적 결과통제에, 정보 확산은 전통적 결과통제에 유의적인 영향을 미치는 것으로 나타났다. 정보특성과 경영통제시스템의 적합성과 경영성과 간의 관계에서는 정보의 전략적 중요성과 행위통제 및 비전통적 결과통제 간의 적합성이 재무적 성과에, 비전통적 결과통제 간의 적합성이 비재무적 성과에 유의적인 영향을 미치는 것으로 나타났으며, 정보 특수성과 행위통제 및 비전통적 결과통제 간의 적합성이 재무적 성과에, 비전통적 결과통제 간의 적합성이 비재무적 성과에 유의적인 영향을 미치는 것으로 나타났고, 정보 확산과 비전통적 결과통제 간의 적합성은 재무적 성과에 유의적인 영향을 미치는 것으로 나타났다. 정보 정형성의 경우는 대체적으로 적합기업 보다 비적합 기업의 경영성과가 높은 것으로 나타났으며, 특히 전통적 결과통제 간의 관계에 있어 비적합 기업의 비재무적 성과가 적합기업 보다 유의적으로 더 높은 것으로 나타났다. 이러한 연구결과는 ERP시스템이 제공하는 정보의 특성에 따라 관리자가 적절한 통제유형을 선택함으로써 경영성과의 개선을 가져올 수 있음을 보여주고 있으며, 전통적 결과통제의 경우 ERP시스템의 실시간 결과정보 제공 특성으로 인해 본 연구에서 사용한 정보의 유형에 따라 선택적으로 사용하기보다 결과정보의 제공정도에 의해 그 활용도가 결정될 개연성을 보여주고 있다.

Performance Improvement of the Horizontal Control System for a Tractor Implement Using Sensor Signal from the Front Axle

( Young-min Ro ),( Jun-hee Moon ),( Kyeong Uk Kim ) 한국농업기계학회 2016 바이오시스템공학 Vol.41 No.2

Purpose: Many tractors have adopted the horizontal control system designed to maintain the three-point mounted implements in horizontal position when they are tilted sideways. The control system rotates the implement in the opposite direction to the inclination of rear axle of the tractor. However, the current control system was found to have poor performance in accuracy and response. A new control system was therefore developed to improve the performance. Methods: The new control system was designed to get the response of the implement to be started earlier by using the tilt information from the front axle of the tractor. By this approach, the rotation of the implement can be adjusted as required to make it horizontal at the expected time, even though the response is slow. The optimal values of the control parameters for the new system were determined by computer simulation and validated by a performance test conducted with an obstacle of 120 mm height on a flat concrete surface. The performance of the control system was evaluated by the root mean square error (RMSE) of the rotation angle of the implement with respect to the actual inclination of the rear axle. Results: The new control system reduced the RMSE of the current control system by 44.6% indicating a high performance improvement. The inclination of the front axle was easily obtained from a sensor mounted on the front axle of the tractor and used as input to the new control system. Conclusions: The method of getting the response of the implement to be started earlier by utilizing the inclination information of the front axle can be applied to improve the performance of the current control system at least cost.

MODEL-BASED CONTROL SYSTEM DESIGN IN A UREA-SCR AFTERTREATMENT SYSTEM BASED ON NH3 SENSOR FEEDBACK

M. DEVARAKONDA,G. PARKER,J. H. JOHNSON,V. STROTS 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.6

This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment system based on NH3 sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with design based on a sliding mode control framework. The control system based on NH3 sensor feedback is analyzed via simulation by comparing it to a control system developed based on NOx sensor feedback. Simulation results show that the NH3 sensor-based strategy performs very similarly in comparison to a NOx sensor-based strategy. The control system performance metrics for NOx index, urea index, urea usage, and NH3 slip suggest that the NOx sensor can be a potential alternative to a NOx sensor for urea-SCR control applications. This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment system based on NH3 sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with design based on a sliding mode control framework. The control system based on NH3 sensor feedback is analyzed via simulation by comparing it to a control system developed based on NOx sensor feedback. Simulation results show that the NH3 sensor-based strategy performs very similarly in comparison to a NOx sensor-based strategy. The control system performance metrics for NOx index, urea index, urea usage, and NH3 slip suggest that the NOx sensor can be a potential alternative to a NOx sensor for urea-SCR control applications.

주식회사(株式會社)의 내부통제제도(內部統制制度)에 관한 연구

정대 ( Dae Chung ) 연세대학교 법학연구원 글로벌비즈니스와 법센터 2010 연세 글로벌 비즈니스 법학연구 Vol.2 No.1

Internal Control-Integrated Framework of Committee of Sponsoring Organizations of the Treadway Commission was published in U.S. in 1992. In 2004, Enterprise Risk Management-Integrated Framework of Committee of Sponsoring Organizations of the Treadway Commission was published. It can be said that Enterprise Risk Management-Integrated Framework contained and developed concept of internal control. In the context of the making of good corporate governance, it is necessary to reinforce and improve internal control system. A company may greatly suffer damages caused by illegal acts or misconduct of employees or the management. In result, establishment of effective internal control system is greatly necessary from the perspectives of corporate governance structure. In addition, as much emphasis has been placed on corporate social responsibility and socially responsible investment fund recently, the importance of establishment of internal control system has been greatly stressed. The competitiveness of the company will be relatively enhanced in a global market if the internal control system is well established. Because of the continued accounting scandals of Enron Energy, and Worldcom, the Sarbanes-Oxley Act of 2002 was enacted in U.S. The Sarbanes-Oxley Act adopted internal control system. According to the Sarbanes-Oxley Act, large corporations in U.S. should establish internal control system. In Japan, internal control system was introduced under the Corporation Code. In addition, the Financial Products Transaction Code of 2006 contained internal control related to a financial report in order to secure confidence of disclosure information in capital market. The reason is that false evaluation of financial position of large companies and illegal acts and misconduct of employees or the management of large companies were continually found. Furthermore, even in Germany, France, England, and China, large corporations should establish internal control system in order to prevent accounting fraud, misconduct, and illegal acts of employees or the management. In Korea, in respect of internal control, a compliance officer should be employed in case of financial institutions and specific large corporations including financial institutions should establish internal accounting management system. Recently, the Supreme Court judged that a director of large corporations had a duty of internal control in the lawsuits in respect of the accounting scandals of the Daewoo Corporation. Therefore, it can be said that a director of large corporations has a duty to establish internal control system and to monitor internal control system. However, there are not any relevant provisions in respect of internal control under the Commercial Code of Korea. Relevant provisions in respect of internal control, therefore, should be codified under the Commercial Code of Korea as soon as possible. Finally, it is necessary to check out and review internal control system from the viewpoint of enterprise risk management.

Integrated Control System for the Beam Commissioning of the PEFP 100-MeV Proton Accelerator

Young-Gi Song 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7

The Proton Engineering Frontier Project (PEFP) has developed an integrated control systemfor beam commissioning of its 100-MeV proton linear accelerator. The final goal of the PEFPcontrol system for beam commissioning is to develop a network of attached and distributed controlsystems. The PEFP control system was designed into the basic control structure of three groupsincluding the central control system, the local control system, and the console system. The centralcontrol system is responsible for the timing synchronization and interlock. The local control systemis responsible for the distributed control system for several linac components, such as the vacuum,power supply, data acquisition, RF, and so on. The console system is responsible for the userinterface as a control system client. In order to implement the control system, we have adopted anExperimental Physics and Industrial Control System (EPICS) software framework as the standarddevelopment tool. The EPICS is based on a distributed architecture that provides several solutions,such as independent programming tools on several hardware and operating-system platforms. TheInput Output Controllers (IOCs) of the PEFP control system have been tested with a wide varietyof hardware solutions from a personal computer to embedded devices. In this paper, we will presentthe details of the integrated control system for beam commissioning of the PEFP 100-MeV protonlinac.