• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1134-1149
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• 2013

Pub/sub system enables data users to access any necessary data without knowledge of the data producer and synchronization with the data producer. It is widely used as the middleware technology for the data-centric services. DDS (Data Distribution Service) is a standard middleware supported by the OMG (Object Management Group), one of global standardization organizations. It is considered quite useful as a standard middleware for US military services. However, it is well-known that it takes considerably long time in searching the Participants and Endpoints in the system, especially when the system is booting up. In this paper, we propose a discovery scheme to reduce the latency when the participants and Endpoints are densely distributed in a small area. We propose to modify the standard DDS discovery process in three folds. First, we integrate the Endpoint discovery process with the Participant discovery process. Second, we reduce the number of connections per participant during the discovery process by adopting the concept of successors in Distributed Hashing scheme. Third, instead of UDP, the participants are connected through TCP to exploit the reliable delivery feature of TCP. We evaluated the performance of our scheme by comparing with the standard DDS discovery process. The evaluation results show that our scheme achieves quite lower discovery latency in case that the Participants and the Endpoints are densely distributed in a local network.

• The Journal of the Korea Contents Association
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• v.20 no.11
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• pp.301-313
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• 2020

This study is a study on the interlocking method between emergency preparedness simulation model and military exercise war game model. The national emergency preparedness government exercises are being carried out by a message exercise and technology development for simulation models is being carried out to create a situation similar to the actual practice. In order to create a situation similar to the actual war, the military situation must be reflected and to do so, a link with the military exercise war game model is needed. The military exercise war game model applies HLA/RTI, which is a standardized interlocking method for various models such as Taegeuk JOS, and it is necessary to apply HLA/RTI linkage method to link with these military exercise war game models. In addition, since the emergency preparedness simulation model requires limited information such as enemy location and enemy attack situation on major facilities in the military exercise model, a method of interlocking that can select and link information is required. Therefore, in this study, the interlocking interface design plan is presented in order to selectively link the interlocking method and information between the emergency preparedness simulation model and the military exercise war game model. The main functions of interlocking interface include federation synchronization, storage and recovery, object management service, time management, and data filtering functions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1364-1373
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• 2016

Ultra High Definition Television (UHDTV) has attracted much attention as one of next generation broadcasting services. For the commercialization of UHD broadcasting service, standardization groups including the DVB (Digital Video Broadcasting) and the ATSC (Advanced Television Systems Committee) have decided to adopt the Orthogonal Frequency Division Multiplexing (OFDM) for signal transmission. However, when the carrier frequency is not properly synchronized at the receiver, inter-symbol interference (ISI) and inter-carrier interference (ICI) may occur. In order to avoid performance degradation resulting from ISI or ICI, receivers should synchronize the carrier frequency by using preambles and pilot symbols. However, there only few published literature dealing with the frequency offset estimation methods regarding the next generation terrestrial broadcasting. In this respect, this paper proposes a method to estimate timing and fractional frequency offset for the ATSC 3.0 system by using a preamble bootstrap symbol. The proposed detector can detect the fractional frequency offset by adding a complex conjugate product on the conventional estimator where only timing offset can be estimated.

• Journal of Life Science
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• v.18 no.8
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• pp.1096-1105
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• 2008

This study was carried out to identify the optimum condition for priming, as a series of experiments for the enhancement of germination percentage and germination synchronization in cool-season turfgrass seeds. The optimum priming conditions to maximize the germinability in both Kentucky bluegrass and Tall fescue was a 1 day treatment of 100 mM $K_3PO_4$ at $25^{\circ}C$. The seeds treated with the optimum priming condition enhanced the germinability compared to control, and shortened the time for germination with reduced $T_{50}$ and mean daily germination (MDG). However, as the concentration and treatment period of NaOH or KOH increased, significantly decrease in germination percentage was observed. Germination percentage in Creeping bentgrass and Bentgrass was below 10%, regardless of priming treatment. However, the priming treatment with 200 mM $KNO_3$ for three days improved the germination up to 6%, which was not a statistically significant level. The most effective priming period for Kentucky bluegrass and Tall fescue was one day treatment, but the germinability was suppressed as the treatment period was extended until six days. For priming chemical treatment, germinability was improved with the concentration of 100 mM, while it was reduced at higher concentrations of 200 mM and 300 mM.

• Journal of Broadcast Engineering
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• v.12 no.1 s.34
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• pp.11-27
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• 2007

T-DMB(Terrestrial-Digital Multimedia Broadcasting) for portable and mobile broadcasting service was officially launched in the metropolitan area of Korea in December 2005. The development of interactive data services and the expansion of T-DMB network have been now progressed, and the regional T-DMB broadcasters will be selected in the near future. Although it is important to evaluate service area and reduce a fringe area for optimizing RF coverage of T-DMB, there was no professional system to support those works, and therefore lots of resources in budget, manpower and time were required. The measurement considering characteristics of SFN(Single Frequency Network) is essential in the implementation of T-DMB network which needs to control synchronization, spacing and output power of transmitters. In addition, mobile measurement, enough measured parameters for many-sided analysis of reception quality, efficient management of enormous measured data and representation of measured results on the electronic map are also important in evaluating service area. In this paper, we derived requirements for a new measurement system in T-DMB by considering the above details, and we proposed and developed an integrated measurement and analysis system. The developed system was applied to the implementation of T-DMB network of KBS and field tests, and it proved its efficiency and accuracy in result.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.526-530
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• 1994

This study was conducted to investigate photosynthetic response to four sequential air influx rate with rice(Oryza sativa L.)plants moved from a natural condition to constant condition with automatic regulation selected environmental variables on 13th~15th days after anthesis. In time course of photosynthetic response to increasing air influx rate(200-280-360-440 ml / min.), stomatal conductance decreased rapidly at the beginning after treatment and then oscillated with a free-running period of a approximately 1 hour to 1 hour 30 minutes until reached up to steady-state condition. Similar change was also observed $CO_2$ assimilation rate. Stomatal conductance decreased throughout the air influx rate sequence, but the rate of decrease was similar to the decrease in $CO_2$ assimilation rate observed under continuous air influx rate conditions. In starch granules during grain filling period under air influx rate(440 ml / min.) , compound starch granules were loosing and a number of hollows were observed in surface of single starch granules. Evidences from several approaches indicate that synchronization of stomatal conductance and$CO_2$ assimilation rate was closely inter-related tinder increase of air influx rate and increase of air influx rate influenced the$CO_2$ uptake in photosynthetic processes and compound starch granule, as 'end products' of photosynthesis.

• Reproductive and Developmental Biology
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• v.32 no.2
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• pp.117-121
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• 2008

Our previous study showed that transgenic (TG) pigs harboring human EPO (hEPO) gene have been shown to have reproductive disorders, including low pregnancy rates, irregular estrus cycle and low little size. To investigate these reasons, we assessed estrus behavior (standing response) and plasma $17{\beta}$-estradiol ($E_2$) level, which partly reflect reproductive function, during the estrus cycles after synchronization and superovulation by hormone treatments. Then, we analysed blood composition and expression of hEPO gene in TG pigs. Pigs were injected with PG600. After 10 days, pigs were fed with Regumate porcine for 6 days. Blood samples were collected from jugular vein. Analysis of blood composition and $E_2$ level were measured by Hemavet 950 and $E_2$ ELISA kit, respectively. And, the expression of hEPO gene in reproductive organs was quantitated by real-time RT-PCR. The percentage of estrus behavior in TG was significantly decreased. Hematocrit (HCT), hemoglobin (Hb) concentration and red blood cell (RBC) number were significantly higher in TG than wild type (WT). On the other hand, high expression of hEPO gene in TG was observed in the mammary gland as well as in the uterus. Moreover, plasma $E_2$ level was significantly higher in TG than WT. These results suggest that nonspecific expression of hEPO gene in the other organs of TG may affect blood composition and plasma $E_2$ level, thereby causing reproductive disorders.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.439-452
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• 2014

This paper suggests the method to extend service area by using the transmit offset delay in T-DMB single frequency network (SFN). In general, synchronization of the transmit time of all site can be done by using the reference clock of GPS, which dose not reflect the details geographical characteristics and transmit specifications of each site. Applying the site-specific transmit offset delay, we could extend the service area of SFN T-DMB. Applying the transmit offset delay, it is found that the signal quality in the region of weak receive field strength was improved and upto 4~8 km service area expansion was achieved by satisfying the minimum field strength ($45dB{\mu}V/m$) recommended by the Korea Communications Commission (KCC). Site-specific offset delay was calculated considering the geographic service area characteristics, distribution of electric field strength between neighboring sites and site-specific service target area. Experiments were carried out in order to analyze impact of calculated offset delay on the T-DMB SFN and also to confirm that the offset delay extends T-DMB service coverage. The experiment was done in metropolitan T-DMB service areas.

• Korean journal of applied entomology
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• v.29 no.4
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• pp.230-237
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• 1990

Studies were carried out to examine seasonal occurrence and emergence pattern of the onion fly, Delia antiqua (Meigen), in the field of Chinju city in Gyeongnam province from 1984 to 1987. Trap catch revealed that the onion fly had three generations in a year, the second flight being partial; the peaks of adult occurrence were at mid April for the overwintered generation (1st flight), at early June for the first generation (2nd flight), and at the period from late September to early October for the autumn generation (3rd flight). It was shown that parts of the pupae in the first and almost all of the pupae in the second (or autumn) generation underwent summer diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapause. The pupal periods were less than 22.4 days for the non-diapaused pupae, while those of the diapaused pupae were form 8.5 to 145 days in the first generation in he filed, being shorter for the pupae pupated later. This resutled in synchronization on the emergence of these diapaused pupae at late September, with the adults from the second generation pupae. The ratio of diapausing pupae increased among the later pupated ones in the first generation ; the pupae which had been pupated in early May included 43.8% of diapausing pupae, while more than 86.7% of the pupae were under diapausing state for the pupae pupated in late May and thereafter. More than 93.3% of the pupae went into diapause, regardless of pupation time for the second generation.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.5
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• pp.16-26
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• 2001

In this paper, we present a new scheduling method called CDSS(Carried-Dependence Self-Scheduling) for efficiently execution of the loop with intra dependency between iterations based on the central queue. We also implemented it on shared memory system using Java language. Also, we study the modification that converts the existing self-scheduling method based on the central task queue for parallel loops onto the same form applied to loop with loop-carried dependences. The proposed method is self scheduling and assigns the loops in three-level considering the synchronization point according to the dependence distance of the loops. To adapt the proposed scheme and modified methods into various platforms, including a uni-processor system, we use threads for implementation. Compared to other assignment algorithms with various changes of application and system parameters, CDSS is found to be more efficient than other methods in overall execution time including scheduling overheads. CDSS shows improved performance over modified SS, Factoring, GSS and CSS by about 0.02, 40.5, 46.1 and 53.6%, respectively. In CDSS, we achieve the best performance on varying application programs using a few threads, which equal the dependence distance.