• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9C
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• pp.955-963
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• 2005

In this paper, we consider the noncoherent code acquisition problem using sequential schemes. We show that the outputs of the noncoherent receiver approximately have a central chi-square distribution under the null hypothesis through simulations. Based on this observation, simplified acquisition schemes are obtained using the approximations of the Bessel function. The performance of the simplified and original schemes are compared in additive white Gaussian noise and slowly varying fading channels. Numerical results show that the simplified schemes have essentially the same performance as the original schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.2991-3000
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• 1996

In this paper, an effective neural acquisition system is suggested for acquisition of the DS/SS communication system. The suggested system uses a binary neural network which geometrically analyzes and learns a given PN sequence in the binary field. the probabilities of detection and false alarm are obtained and are compared to simulation values. The equation of the mean acquisition time is derived and is compared to the doubledwell time of the serial serial search system. The significant improvement of the performance is demonstrated. As the length of synchronization sequence becomes longer and the number is increased, the performance is improved.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1697-1698
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• 2008

PLS(Pohang Light Source) is 2.5 Gev synchrotron radiation source in Pohang, Korea, which is under operation since 1995. The hardware and software of the old BPM(Beam Position Monitor) data acquisition system for the PLS storage ring was completely upgraded to increase its performance and stability. The new BPM data acquisition system is based on VME-based EPICS (Experimental Physics and Instrument Control System) IOC system. We used 16-bit resolution analog-to-digital conversion board to digitize analog BPM signals. We developed a data average software to average raw BPM data using reflective memory board. We also developed device drivers for VME I/O boards used, IOC database for PV's(Process Variables). The new BPM data acquisition system is currently running for routine operation with good performance and stability. In this paper, we present the hardware and software of the new BPM data acquisition system DTL water skid cooling system and Resonant Control Cooling.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.123-129
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• 2020

The objective of this study is to examine the differentiated influence of sell-side advisors and buy-side advisors on mergers and acquisitions (M&A). Unlike prior studies on M&A advisors, the study addresses different roles of target and acquirer advisors, and explores their influences on the cumulative abnormal returns (CAR) and acquisition premiums with an empirical analysis of longitudinal data of M&As conducted by Japanese listed firms except financial companies from 1995 to 2012. M&A data were obtained from the Securities Data Corporation's (SDC) database, and the individual firm data were collected from the Nikkei Economic Electronic Databank System (NEEDS), which provides a wide range of corporate information including financial status, operational performance, and strategy. Using a sample of 452 cases for the CAR and 498 cases for the analysis of acquisition premiums, the empirical results support the hypotheses of the target advisor's positive association with CAR and acquirer advisor's positive association with acquisition premiums. The findings of this study indicate the target advisor's positive contribution to the success of acquisition process and performance, and acquirer advisor's negative influence on the deal progress. The study provides theoretical implications on M&A research and practical insights into the investment banking industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2C
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• pp.200-207
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• 2008

In this paper, a new detector is proposed for code acquisition, which employs the signs and ranks of the received signal samples, instead of their actual values, and so does not require knowledge of the non-Gaussian noise dispersion. The mean acquisition performance of the proposed detector is compared with that of the detector of $^{[1]}$. The simulation results show that the proposed scheme is not only robust to deviations from the true value of the non-Gaussian noise dispersion, but also has comparable performance to that of the scheme of $^{[1]}$ using exact knowledge of the non-Gaussian noise dispersion.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.416-423
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• 2012

Liquid acquisition device in the liquid propellant supply system is required to protect entrance of gas bubble into the propulsion system. The device exploits the capillary effect of micro-sized poles in a screen and supplies pure liquid-phase propellant to the propulsion system. The bubble point is the most important performance parameter in the design of a liquid acquisition device. In this paper, performance parameters affecting the bubble point are identified through literature survey, in order to develop the experimental setup for the bubble point measurement.

• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.218-223
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• 2020

There are communication methods that guarantees real-time and method of performing the simultaneous acquisition through the synchronized multi-channels to improve the reliability of the telemetry system. Such synchronized systems need to be verified to confirm the simultaneous measurement performance of channels. In this paper, we propose a method to measure the time difference between synchronized channels in a telemetry system through simultaneous acquisition performance test. The simulation signal is applied for measurement and the difference between the sampling period and the simulation signal period is defined as the concept of time resolution. The principle of checking the measurement time difference between channels through time resolution was explained. In addition, the proposed principle was verified through simulation in the situation when measurement time difference may occur. And a procedure for identifying a measurement time difference in an actual telemetry system is described.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.9
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• pp.9-17
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• 1999

In this paper, we present a mathematical modeling and perform a performance analysis of double-dwell serial search algorithm, which has a search window concept, for pilot channel in DS-CDMA(Direct Sequence Code Division Multiple Access). We derive a code detection function, a false alarm function, a code miss function, and a mean code acquisition time for the performance analysis. We calculate the mean code acquisition time of the mathematical model in IS-95 forward link and compare it with that of the conventional search methods. The performance of the code acquisition system is also evaluated to investigate the effect of dwell times and search window size. The JTC channel model, which is a PCS channel model in North America, is used for the analysis. The numerical result shows that the mean code acquisition time of the double-dwell serial search algorithm with a search window is reduced by about 17%~25% than those of the conventional ones.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.1
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• pp.1-8
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• 2013

A signal system for improving the code acquisition complexity of Global Navigation Satellite System (GNSS) receiver is proposed and the receiving correlator scheme is presented accordingly. The proposed signal system is a hierarchical code type with a duplexing configuration which consists of the Zadoff-Chu (ZC) code having a good auto-correlation characteristic and the Pseudo Random Noise (PRN) code for distinguishing satellites. The receiving correlator has the scheme that consists of the primary correlator for the ZC code and the secondary correlator which uses the PRN code for the primary correlation results. The simulation results of code acquisition using the receiving correlator of the proposed signal system show that the proposed signal scheme improves the complexity of GNSS receiver and has the code acquisition performance comparable to the existing GNSS signal system using Coarse/Acquisition (C/A) code.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.4
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• pp.151-160
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• 2015

GPS L2C signal is a recently added civil signal to L2 frequency and is constructed by time division multiplexing of civil moderate (L2-CM) and civil long (L2-CL) code signals. While the L2-CM code is 20 ms-periodic and modulates satellite navigation message, the L2-CL code is 1.5s-periodic with 767,250 chips long code sequence and carries no data. Therefore, the L2-CL code signal allows receivers to perform a very long coherent integration. However, due to the length of the L2-CL code, the acquisition of the L2-CL code signal may take too long or require too much hardware resources. In this paper, we propose a three-step ultra-fast L2-CL code acquisition (TSCLA) technique for dual band GPS receivers. In the proposed TSCLA technique, a dual band GPS receiver sequentially acquires the coarse/acquisition (C/A) code signal at L1 frequency, the L2-CM code signal, and the L2-CL code signal to minimize mean acquisition time (MAT). The theoretical performance analysis and numerous Monte Carlo simulations show the significant advantage of the proposed TSCLA technique over conventional techniques introduced in the literature.