• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.158-158
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• 2015

대부분의 대규모 배수지는 고지대에 위치함으로써 자연유하를 통해 배, 급수지역으로 용수를 공급한다. 이를 위해 배수지 전단에는 가압장이 위치하여 정수장에서 처리된 용수를 고지대에 위치한 배수지로 송수한다. 이때 가압장에서 발생하는 전력소비량이 매우 높은 것으로 알려져 있으며, 효율적인 펌프운영을 통해 상당한 전력비용 절감이 가능할 것으로 판단된다. 일반적인 가압장의 운영은 시스템 운영자의 경험을 토대로 해당 가압장에 연결된 배수지의 수위에 따라 펌프의 작동여부를 결정하는 방법이 주로 사용되고 있다. 이러한 운영방법은 용수공급의 안전성을 우선시함으로써 배수지의 수위를 일정하게 유지하고자 빈번하게 펌프를 작동하게 되고 따라서 가압장에서 소모되는 전력량이 커서 운영효율 측면에서는 바람직하지 않다고 할 수 있다. 또한 빈번한 펌프의 작동으로 인해 펌프의 수명이 단축될 뿐만 아니라, 배수지내 용수의 수질저하 문제도 발생할 수 있다. 본 연구에서는 효율적인 펌프장 운영을 위해 급수지역의 24시간 용수사용량을 예측하고, 그에 따른 펌프장의 가압 유량 및 양정을 파악하여 적정용량의 펌프를 선정하고 운영함으로써 펌프의 운영비용의 최소화 및 안정적인 용수공급을 동시에 달성하고자 한다. 이를 위해, 실시간 최적화 모형을 개발하였다. 개발된 최적화 모형은 상수관망해석 프로그램(EPAENT)을 연계하여 수요절점의 수압조건 및 운영상황을 모의하였다. 최적화 기법으로는 유전자알고리즘을 사용하였으며, 실제 시스템의 운영상황를 반영하기 위한 다양한 제약조건(operational constraints)을 적용하였다. 개발된 모형은 정속펌프(혹은 On/Off 펌프) 뿐만 아니라, 최근 실무에서 널리 사용되고 있는 변속펌프(variable speed pump)를 추가적으로 고려하였다. 개발된 모형은 국내에서 실제 운영되고 있는 송, 배수 시스템에 적용하여 모형의 실무 적용가능성을 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.401-404
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• 2010

고성능 단말기와 다양한 컨텐츠가 제공되면서 제스처 기반 사용자 인터페이스에 대한 관심이 높아지고 있다. 하지만 기존의 알고리즘을 사용하기 위해서는 센서 장치를 사용하거나 사용자가 부자연스러운 장비를 착용해야 하는 경우가 많다. 본 논문에서는 카메라를 통해 입력된 영상 정보만으로 사용자가 착용한 색상 마커를 실시간으로 검출하는 알고리즘을 제안한다. 본 논문이 제안하는 마커 인식 알고리즘은 색상 감지와 움직임 감지로 나뉜다. 단일 프레임에서 영상 성분 평균을 이용한 조건검사를 통하여 색상 영역을 검출한다. 다음으로, 인접한 프레임간의 평균 영상과 현재 영상과의 차를 가중치로 이용하여 배경 범위를 설정하고 이 범위를 벗어난 영역을 움직임 영역으로 검출한다. 마지막으로 색상 검출 영역과 움직임 검출 영역을 동시에 만족하고 이웃한 픽셀들도 위 조건을 동시에 만족하면 최종적으로 사용자의 마커로 인식한다. 본 논문이 제안하는 알고리즘은 영상 정보만 사용하기 때문에 사용자는 센서나 부자연스러운 장비를 착용할 필요가 없고 일조량에 따른 조도의 변화에 강건하기 때문에 효과적인 사용자 움직임 검출이 가능하다.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.533-542
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• 2001

In this paper, we present a scheduling method for real-time mobile transaction manager in mobile computing environment. The proposed method checks whether a transaction is executable or not. It is able to by considering not only the deadline of real-time data in mobile hosts. And then, it schedules the real-time mobile transactions by making optimal execution window based on the priority queue, while considering transaction value and deadline. Disconnection with mobile hosts is monitored in selecting the transaction for execution. Using the proposed method reduces the number of restarting times after transaction aborts which is caused by the violation of the validity constraints of real-time data. And in has merits of maximizing the sum of values of real-time mobile transactions which meet the deadline. The performance evaluation demonstrates that the number of committed real-time transactions within the deadline is improved by 20%. This method can be used in real-time mobile transaction manager is such environments as cellular communications, emergency medicine information system and so on.

• Journal of Korea Game Society
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• v.19 no.1
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• pp.5-14
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• 2019

This paper presents a practical method to compute the closest approach distance of two ellipsoids in their inter-center direction. This is the key technique for collision handling in the dynamic simulation of rigid and deformable bodies approximated with ellipsoids. We formulate a set of equations with the inter-center distance and the contact point and normal for the two ellipsoids contacting each other externally. The equations are solved using fixed-point iteration and Aitken's delta-squared process. In addition, we introduce a novel stopping criterion expressed in terms of the error in distance. We demonstrate the efficiency and practicality of our method in various experiments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.3
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• pp.263-272
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• 2001

For a high resolution real-time kinematic GPS surveying using carrier phase, positioning accuracy according to the OTF initialization was better than 1 cm with more than 5-minute initialization within 20 km baseline. Also, it is recommended that measurements be carried out when PDOP and RDOP can be kept less than 4.0 since the geometrical layout of satellites has a great influence on the positioning accuracy. After considering the initial conditions and measuring time zone for real-time kinematic GPS. post-processed continuous kinematic GPS and real-time kinematic GPS measurements have been carried out. A new system has been proposed to store measured data by using a program developed to store GPS data in real time and to monitor the satellite condition through controller at the time of measurement. As a result, it has been revealed that possible noise in surveying could be corrected and the accuracy could be improved.

• Journal of the Korea Computer Industry Society
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• v.3 no.9
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• pp.1167-1176
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• 2002

In a (hard) real-time system, every time-critical task must meet its timing constraint, which is typically specified in terms of its deadline. Many computer systems, such as those for open system environment or multimedia services, need an efficient schedulability test for on-line real-time admission control of new jobs. Although various polynomial time schedulability tests have been proposed, they often fail to decide the schedulability of the system precisely when the system is heavily loaded. Furthermore, the most of previous studies on on-line real-time schedulability tests are concentrated on periodic task applications. Thus, this paper presents an efficient on-line real-time schedulability check algorithm which can be used for imprecise real-time system predictability before dispatching of on-line imprecise real-time task system consisted of aperiodic and preemptive task sets when the system is overloaded.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.173-186
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• 2000

Real-time embedded systems should accommodate many kinds of hardware platforms and resource management policies that vary depending on their operating environments and purposes. It is not an easy job to adapt a multitasking kernel to new system services and hardware platforms, as the kernel must strictly satisfy constraints on its size and performance. This paper describes the design and implementation of an object-oriented multitasking framework that can be reused for implementing microprocessor-based real-time embedded multitasking kernels, In this kernel framework, those parts that can vary depending on hardware platforms and system resource management policies are separated into the hot spots and encapsulated by abstract classes. Our framework thus can be effectively used to implement microprocessor-based real-time embedded kernels that demand high portability and adaptability.

• The KIPS Transactions:PartD
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• v.12D no.5 s.101
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• pp.709-718
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• 2005

To correspond with the unpredictable future tactical environment, Ive expanded the application of M&S(Modeling & Simulation) that is more scientific and more economic in a field of weapon system development process. This paper describes experience in development of ADSF(Air Defense Simulation Framework) that supports not only HLA(High Level Architecture) which is an international standard in M&S but also TCP/IP as well as real-time distributed simulation. ADSF has been applied to the M-SAM(Medium Range Surface to Air Missile) System Simulator, and satisfying test results through GPS(Global Positioning System) timer has been acquired. As a result, an ADSF which is able to support HLA and TCP/IP as veil as precise real-time simulation has been successfully made. we were in need or a real-time simulation engine to support Air Defense System Simulators that were consisted of several subsystems.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.449-458
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• 1999

In real-time systems, the accurate response time and minimal communication delay is highly desired. However, a conventional SNMP uses network resources inefficiently and introduces too much network traffic for periodic requests in particular. This paper presents an extended SNMP called Real-Time SNMP. It is designed to support real-time applications with time constraints to provide more accurate response time and less network traffic for periodic SNMP request PDU which is sent from a management station to agents. In addition, the module of the Real-Time SNMP agent works between management station and each SNMP agent to periodically generate requests for the associated agent. In this paper we have implemented the proposed Real-Time SNMP agent module and extended SNMP PDU. We also show the experimental results that indicated more punctual response time and reduced communication delay using the proposed Real-Time SNMP.

• The KIPS Transactions:PartA
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• v.16A no.6
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• pp.463-472
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• 2009

Real-time operating systems must have satisfying various conditions such as effective scheduling policies, minimized interrupt delay, resolved priority inversion problems, and its applications to be completed within desired deadline. The real-time operating systems, therefore, should be designed and developed to be optimal for these requirements. MicroC/OS-II, a kind of Real-time operating systems, uses the basic priority inheritance with a mutex to solve priority inversion problems. For the implementation of mutex, the kernel in an operating system should provide supports for numerous tasks with same priority. However, MicroC/OS-II does not provide this support for the numerous tasks of same priority. To solve this problem, MicroC/OS-II cannot but using priority reservation, which leads to the waste of unnecessary resources. In this study, we have dealt with new design a protocol, so called TPSP(Temporary Priority Swap Protocol), by an effective solution for above-mentioned problem, eventually enabling embedded systems with constrained resources environments to run applications.