• Journal of Radiation Industry
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• v.4 no.1
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• pp.85-89
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• 2010

The radioactive experiments are carried out for diagnosis of a variety of industrial processes in terms of the operation condition and the efficiency by measuring the residence time distribution. However, it is not easy to interpret the residence time distribution using the conventional methods when the flow rate is not constant and a number of processes are coupled in a complicated manner. In these cases, they can be analyzed by describing the system with mathematical models that can be defined with the state-space equations. In this paper, the residence time distribution of sludge was measured with a radiotracer, $^{46}Sc-EDTA$, in the digester of which the flow rate varies with time. The digester was assumed as a linear time variant system since the flow rate changed during the experiment and the operation efficiency of the digester was calculated by applying the state-spae equations.

• 한국가스학회:학술대회논문집
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• no.5
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• pp.111-118
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• 2002

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2455-2458
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• 2005

In this paper, we analyzed the effect of a training system for improving equilibrium sense. This training system consists of an unstable platform, a force plate, a computer, and training programs. Using the system with training programs, we performed various experiments to train the equilibrium sense of fifteen subjects. To evaluate the effect of the training system, we measured the time a subject maintains a focus, the moving time to the target, and the absolute deviation of the trace. We analyzed these parameters obtained before and after the training using paired-samples T-test. The results showed that the subjects experienced a distinctive enhancement of their equilibrium senses through the training using our system.

• 전자공학회논문지 IE
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• v.44 no.3
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• pp.51-55
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• 2007

In this paper, we consider the controllability and observability for the time-varying linear system using the input-state(I/O), input-output(I/O) transformation and get the time-invarying linear system. The transformed system represent the system with the multiple integral. We verify the proposal algorithm via the example and examine.

• 전자공학회논문지 IE
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• v.43 no.3
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• pp.28-33
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• 2006

In this paper, we consider the input-output(I/O) transformation for the time-varying linear system and get the time-invarying linear system. And we present the necessary sufficient condition for the I/O transformation. The transformed system represent the system with the multiple integral. We verify the proposal algorithm via the example and examine.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.245-255
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• 2023

Time comparison techniques are necessary for generating and keeping Coordinated Universal Time (UTC) and distributing standard time clocks. Global Navigation Satellite System (GNSS) Common View, GNSS All-in-View, Two-Way Satellite Time and Frequency Transfer (TWSTFT), Very Long Baseline Interferometry (VLBI), optical fiber, and Network Time Protocol (NTP) based methods have been used for time comparison. In these methods, GNSS based time comparison techniques are widely used for time synchronization in critical national infrastructures and in common areas of application such as finance, military, and wireless communication. However, GNSS-based time comparison techniques are vulnerable to jamming or interference environments and it is difficult to respond to GNSS signal disconnection according to the international situation. In response, in this paper, Code-Division Multiple Access (CDMA) based All-to-All TWSTFT operation method is proposed. A software-based simulation platform also was designed for performance analysis in multi-TWSTFT signal environments. Furthermore, code and carrier measurement jitters were calculated in multi-signal environments using the designed simulation platform. By using the technique proposed in this paper, it is anticipated that the TWSTFT-based time comparison method will be used in various fields and satisfy high-performance requirements such as those of a GNSS master station and power plant network reference station.

• The Journal of Information Technology and Database
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• v.1 no.2
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• pp.103-125
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• 1994

In this paper, we introduce a new main memory storage system called FLASH that is designed for real-time applications. The FLASH system is characterized by the memory residency of data and a new fast and dynamic hashing scheme called extendible chained bucket hashing. We compared the performance of the new hashing algorithm with other well-known ones. Also, we carried out an experiment to compare the overall performance of the FLASH system with a commercial one. Both comparison results show that the new hashing scheme and the FLASH system outperforms other competitives.

• Journal of the Korean Ceramic Society
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• v.45 no.5
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• pp.280-284
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• 2008

In order to investigate residence time effect on the growth of ZrC film, the ZrC films grew with various system total pressure (P) and total flow rate (Q) by low pressure chemical vapor deposition because residence time is function of system total pressure and total flow rate. Thermodynamic calculations predict that the decomposition of source gases ($ZrCl_4$ and $CH_4$) would be low as increasing the residence time. Thermodynamic calculations results were proved by investigating deposition rate with various residence time. Deposition rate decreased with residence time of source gas increased. Besides, depletion effect accelerated diminution of deposition rate at high residence time. On the other hands, the deposition rated was increased as decreasing the residence time because fast moving of intermediate gas species decrease the depletion effect. The crystal structure was not changed with residence time. However, the largest size of faceted grain showed up to specific residence time and the size of grain was decreased whether residence time increase or not.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.573-575
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• 2007

Current accuracy of GPS is within the meter level, which is sufficient for route guidance of car navigation system(CNS). But receiving condition of GPS signal varies time to time according to surrounding objects such as building, trees, and terrain. For this reason, the performance of the route guidance is degraded in urban region. In this paper, to improve the performance of the route guidance of CNS, we propose a method for determining location of vehicle using a location of the traffic signal and its pixel size extracted from real-time Image.