• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.25-32
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• 2006

Weapon systems composed of several subsystems execute various engagement missions in distributed combat environments in cooperation with a large number of subordinate/adjacent weapon systems as well as higher echelons through tactical data links. Such distributed weapon systems require distributed real-time simulation test beds to integrate and test their operational software, analyze their performance and effects of cooperated engagement, and validate their requirement specifications. These demands present significant challenges in terms of real-time constraints, time synchronization, complexity and development cost of an engagement simulation test bed, thus necessitate the use of high-performance distributed real-time simulation architectures, and modeling and simulation techniques. In this paper, in order to meet these demands, we presented a distributed real-time simulation system based on High Level Architecture(HLA) and Discrete Event System Specification(DEVS). We validated its performance by using it as a test bed for developing the Engagement Control System(ECS) of a surface-to-air missile system. The proposed technique can be employed to design a prototype or model of engagement-level distributed real-time simulation systems.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.6
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• pp.195-208
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• 2022

The role of venture CEO and their intrinsic capabilities on organizational performance can be determined by the level of resource synchronization initiated by the focal managers. Despite the important role of venture CEOs, a systematic lack of in-depth theoretical and empirical studies on ruminating the relationship between the effects of a CEO's capabilities and organizational performance depending on the level of resource synchronization exist for the rationale of investigation. To supplement the limitations of previous studies, this research empirically analyzes the role of managers specifically synchronizing organizational resources that affect organizational performance in the professional sports industry. Based on the entrepreneurship theory and resource-based view (RBV), this research conceptualizes the roles of venture CEO and basketball head coach in the professional sports industry as very similar in terms of organizational structure and performance mechanism embedding entrepreneurial characteristics necessary for managing organizational resources. In this research, we hypothesized (1) organizational resource synchronization will mediate the positive relationship between the ability of professional basketball head coach and organizational performance and (2) the indirect effect of the professional basketball head coach's capabilities on organizational performance mediated by resource synchronization will be moderated by the capabilities of players. To test these hypotheses, we utilized the PROCESS macro model 58 with the empirical data of 9 seasons (2013~2014-2021~2022) of 30 National Basketball Association (NBA) and 10 Korean Basketball League (KBL) teams. The statistical results showed that (1) resource synchronization mediates the positive relationship between professional basketball head coach capabilities and organizational performance and (2) the capabilities of players moderated the indirect effects of the abilities of head coaches on team performance via resource synchronization. This paper contributes to both academic and practical domains of entrepreneurship by empirically testing the research model through objective professional sports data.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.469-478
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• 2001

It is difficult to test a distributed system because of the task of controlling concurrent events,. Existing works do not propose the test sequence generation algorithm in a formal way and the amount of message is large due to synchronization. In this paper, we propose a formal test sequence generation algorithm using logical clock to control concurrent events. It can solve the control-observation problem and makes the test results reproducible. It also provides a generic solution such that the algorithm can be used for any possible communication paradigm. In distributed test, the number of channels among the testers increases non-linearly with the number of distributed objects. We propose a new remote test architecture for solving this problem. SDL Tool is used to verify the correctness of the proposed algorithm and it is applied to the message exchange for the establishment of Q.2971 point-to-multipoint call/connection as a case study.

• Journal of Mechanical Science and Technology
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• v.19 no.11
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• pp.2040-2052
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• 2005

The present paper centers on the establishment of a quantified relationship between the macroscopic visual parameters of a Diesel spray and its most influential factors. The factors considered are the ambient gas density, as an external condition relative to the injection system, and nozzle hole diameter and injection pressure as internal ones. The main purpose of this work is to validate and extend the different correlations available in the literature to the present state of the Diesel engine, i.e. high injection pressure, small nozzle holes, severe cavitating conditions, etc. Five mono-orifice, axi-symmetrical nozzles with different diameters have been studied in two different test rigs from which one can reproduce solely the real engine in-cylinder air density, and the other, both the density and the pressure. A parametric study was carried out and it enabled the spray tip penetration to be expressed as a function of nozzle hole diameter, injection pressure and environment gas density. The temporal synchronization of the penetration and injection rate data revealed a possible explanation for the discontinuity observed as well by other authors in the spray's penetration law. The experimental results obtained from both test rigs have shown good agreement with the theoretical analysis. There have been observed small but consistent differences between the two test rigs regarding the spray penetration and cone angle, and thus an analysis of the possible causes for these differences has also been included.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.2
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• pp.170-177
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• 2011

This paper proposes a telemetering method that transmits the real-time data together with the time-delayed data and that merges both data after flight test. The method can minimize the error data which occur in the communication environment affected by the multipath fading and transmit antenna pattern when telemetry data are received during the flight test. This method was applied to the design of the telemetry unit and the development of data merging program. By merging the resulting data of flight test and analyzing synchronization errors, its efficiency for the telemetry link is verified.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.774-780
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• 2009

The objectives of this study were to test the efficacy of induction of estrus and determine the timing of ovulation in relation to preovulatory LH and estrogen surges in cycling Murrah buffaloes subjected to Heatsynch protocol (GnRH-$PGF_2{\alpha}$-Estradiol benzoate). In experiment 1, the buffaloes (n = 10) were treated with Heatsynch protocol and observed for estrus and ovulation. In experiment 2 and 3, 30 cycling Murrah buffaloes were used to investigate the efficacy of Heatsynch protocol in terms of conception rates in summer (experiment 2) and winter (experiment 3) seasons. Fixed time A.I. was performed in all the buffaloes at 48 and 60 h post-estradiol benzoate (EB) injection. All buffaloes responded to the Heatsynch protocol with expression of estrus for which ovulations were induced in 8 buffaloes (80%). Mean time interval from the EB injection to ovulation was 50.0${\pm}$2.0 h (range 44.0 to 60.0 h). The interval from the end of LH surge to ovulation was 18.5${\pm}$2.47 h (range 8 to 26 h). The interval from end of estrogen surge to ovulation was 26.75 ${\pm}$2.07 h (range 22 to 36 h). Mean LH peak after EB injection occurred at 20.81${\pm}$1.61 h (range 14 to 28 h) and mean estrogen peak after EB injection occurred at 9.62${\pm}$1.03 h (range 7 to 16 h). Hence, the mean estrogen peak preceded the mean LH peak by 11 h. It was observed that the percentage of conceptions to total number of estruses for control buffaloes was 18 and 30 in summer and winter, respectively, whereas it increased to 26 and 40 in Heatsynch treated buffaloes in respective seasons. The results suggest the possibility of using Heatsynch treatment followed by fixed time A.I. in buffaloes for fertility improvement, especially since the incidence of silent heat in buffaloes is very high.

• Journal of Energy Engineering
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• v.5 no.2
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• pp.153-159
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• 1996

The Sequence Of Event (SOE) system used in nuclear power plants is a part of the Plant Data Acquisition System (PDAS). The SOE system of the existing nuclear power plant shares the computer H/W and S/W with PDAS, and requires more complicated structure using three processors to provide the events or trip signals. Moreover, there are high potential of collision between synchronization signals and data transmitted to the Plant Computer System (PCS) when the synchronization signals are sent from PCS to the three SOE processors. When this collision happens the SOE system will break down, thus it is not possible to analyze the trend of events or trips. This paper issues the limitations item of the existing SOE system and proposes the novel SOE system using single processor. And the test system for proposed SOE system is designed, implemented and tested.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.64-71
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• 2009

This paper presents an efficient frame synchronizer architecture using the common autocorrelator for Digital Video Broadcasting via Satellite, Second generation(DVB-S2). To achieve the satisfactory performance under severe channel conditions and the efficient hardware resource utilization of functional synchronization blocks which have been implemented, we propose a new efficient common autocorrelator structure. The proposed architecture can improve the performance of the frame and frequency synchronizer since each block operates jointly in parallel and significantly reduce the complexity of the frame synchronizer. Hence, The proposed architecture can ensure the decrease by about 92% multipliers and 81% adders compared with the direct implementation. Moreover, it has been thoroughly verified with an FPGA board and R&STM SFU broadcast test equipment and consists of 29,821 LUTs with XilinxTM Virtex IV LX200.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1904-1917
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• 2016

The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of phase-locked loops (PLLs). This is of vital significance for the grid-integration and stable operation of power electronic converters to electric power systems. However, the open-loop bandwidth is drastically reduced after incorporating a MAF into the PLL structure, which makes the dynamic response sluggish. To overcome this shortcoming, some new techniques have recently been proposed to improve the transient response of MAF-based PLLs. In this paper, a comprehensive performance comparison of advanced MAF-based PLL algorithms is presented. This comparison includes HPLL, MPLC-PLL, QT1-PLL, and DMAF-PLL. Various disturbances, such as grid voltage sag, voltage flicker, harmonics distortion, phase-angle and frequency jumps, DC offsets and noise, are considered to experimentally test the dynamic performances of these PLL algorithms. Finally, an improved positive sequence extraction method for a HPLL under the frequency jumps scenario is presented to compensate for the steady-state error caused by non-frequency adaptive DSC, and a satisfactory performance has been achieved.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.485-492
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• 2009

In the mobile service environment, patterns generated by temporal synchronization are streamed with different instance values. This paper proposed a variable clustering management method, which manages multiple data streaming dynamically, to support flexible clustering. The method manages synchronization effectively and differently with conventional streaming methods in data streaming environment and manages clustering streaming after the structural presentation level and the fitness presentation level. In the structural presentation level, the stream structure is presented using level matching and accumulation matching, and clustering management is carried out by the management of dynamic segment and static segment. The performance of the proposed method is tested by using k-means method, C/S server method, CDN method, and simulation. The test results showed that the proposed method has better performance than the other methods.