• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.6A
• /
• pp.586-592
• /
• 2006

In this paper, a novel detection method called the joint multiple frequency cell (JMFC) detection is addressed for spread spectrum code acquisition in the presence of residual Doppler frequency offset (RDFO). When the RDFO exists, the correlation peak used for detection during the acquisition process is split into several lower neighboring peaks, resulting in severe degradation in the detection performance, and consequently, in the overall acquisition performance. In the JMFC detection, a decision variable for detection is formed by combining several consecutive correlator outputs, so that the reduction in the correlation value due to the RDFO can be alleviated. Numerical results show that the proposed scheme can offer better detection performance over the conventional scheme based on the cell-by-cell detection.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.9 no.1
• /
• pp.43-51
• /
• 1998

In this paper, the performance about the CDMA inital synchronization under the Rician fading channel, which is actively studied as a CAI for IMT2000(FPLMTS) is analyzed. Through the performance analysis with the double dwell serial search code acquisition, the minimum mean initial synchronization acquisition time vs signal detection threshold value and first dwell duration time respectively with parameters of false alarm probability, detection probability and test PN chips is presented and the results show the mean initial synchronization acquisition time is increased with lower slope than Rayleigh fading as the threshold value of the initial synchronization acquisition decision is increased.

• Journal of Korea Technology Innovation Society
• /
• v.9 no.4
• /
• pp.884-908
• /
• 2006

The focus of this study is to analyze the link between existing knowledge in the organization and NPD performance. After a comprehensive literature review, we identified factors influential in the management of existing knowledge, such as efficiency of information acquisition, shared interpretation, structure of organization. Through an empirical research, we found that existing knowledge was positively associated with the efficiency of information acquisition and shared interpretation. Additionally, a strong relationship was found between information acquisition efficiency and NPD. Shared information, however, was not found to be associated with NPD. This result, make us recognize the necessity to better understand some subprocesses through which existing knowledge affects new product performance.

• Journal of Aerospace System Engineering
• /
• v.15 no.6
• /
• pp.42-49
• /
• 2021

To develop a high-resolution electro-optical/infrared (EO/IR) payload to be mounted on a high-speed and performance fighter aircraft in an external POD for acquiring daytime and nighttime image information on tactical targets, simulations, including flight environments and maneuvers, should be performed. Such simulations are pertinent to predicting the performance of several variables, such as aerodynamic force and inertia load acting on the payload. This paper describes the development of a flight data acquisition and analysis system based on flight simulation software (SW) for mission simulation of super-maneuverability fighter equipped with EO/IR payload. The effectiveness of the system is verified through comparison with actual flight data. The proposed flight data acquisition and analysis system based on FlightGear can be used as an M&S tool for system performance analysis in the development of the EO/IR payload.

• Journal of Information Science Theory and Practice
• /
• v.10 no.3
• /
• pp.24-39
• /
• 2022

Online learning is becoming ubiquitous worldwide because of its accessibility anytime and from anywhere. However, it cannot be successfully implemented without understanding constructs that may affect its adoption. Unlike previous literature, this research extends the Unified Theory of Acceptance and Use of Technology with three well-known theories, namely compatibility, online self-efficacy, and knowledge sharing and acquisition to examine online learning adoption. A total of 264 higher education students took part in this research. Partial Least Squares-Structural Equation Modeling was used to evaluate the proposed theoretical model. The findings suggested that performance expectancy and compatibility were significant predictors of behavioral intention, whereas behavioral intention, facilitating conditions, and compatibility had a significant and direct effect on online learning's actual use. The results also showed that knowledge acquisition, knowledge sharing, and online self-efficacy were determinates of performance expectancy. Finally, online self-efficacy was a predictor of effort expectancy. The proposed model achieved a high fit and explained 47.7%, 75.1%, 76.1%, and 71.8% of the variance of effort expectancy, performance expectancy, behavioral intention, and online learning actual use, respectively. This study has many theoretical and practical implications that have been discussed for further research.

• Physical Therapy Korea
• /
• v.23 no.4
• /
• pp.16-26
• /
• 2016

Background: Deficiencies in the ability to maintain balance are common in elderly. Augmented feedback such as knowledge of results (KR) can accelerate learning and mastering a motor skill in older people. Objects: We designed this study to examine whether one session of Wii-Fit game with self-regulated KR is effective for elderly people, and to compare the effect of two different timings of self-regulated KR conditions. Methods: Thirty-nine community-dwelling elders, not living in hospice care or a nursing home, participated in this study. During acquisition, two groups of volunteers were trained in 10 blocks of a dynamic balancing task under the following 2 conditions, respectively: (a) a pre-trial self-regulated KR ($n_1=18$), or (b) a post-trial self-regulated KR ($n_2=21$). Immediate retention tests and delayed retention tests of balancing performance were administered in 15 minutes and 24 hours following acquisition period, respectively. Results: In both groups, significant improvements of balancing performances scores were observed during the acquisition period. Regardless of the group, mean of balancing performance scores on retention tests were well-maintained from the final session. There were no significant differences between groups in balancing performance scores during the acquisition period (p>.05); however, the post-trial self-regulated KR group exhibited significantly higher balancing performance scores in both the immediate retention test and delayed retention test than that of the pre-trial self-regulated KR group (p<.05). Conclusion: Therefore, subjects who regulated their feedback after a dynamic balancing task, during the acquisition period, experienced more efficient motor learning during the retention period than did subjects who regulated their feedback before a dynamic balancing task. Accordingly, in case of presenting the KR of motor learning in clinical settings to elders who reduced dynamic balance abilities, the requesting time of KR is imperative according to self-estimation processes as well as types of KR and practice.

• Journal of information and communication convergence engineering
• /
• v.9 no.3
• /
• pp.305-309
• /
• 2011

This paper proposes a new rotational frequency detector (RFD) for phase-locked loop (PLL) or clock and data recovery (CDR) applications for fast frequency acquisition. The proposed RFD uses the four states finite state machine (FSM) model to accelerate the frequency acquisition time. It is modeled and simulated with MATLAB Simulink. The functionalities of the proposed RFD are examined and the results are compared to those of a conventional RFD. The proposed RFD's frequency acquisition time is four times faster than that of a conventional one. The proposed RFD incorporated with a phase detector (PD) in PLL or CDR is expected to improve the frequency and phase acquisition performance later greatly.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.6
• /
• pp.603-607
• /
• 2008

This paper proposes a fast acquisition method using INS velocity and multiple correlators for high speed vehicles. In order to reduce acquisition time in GPS receiver, the method utilizes inertial velocity information and multiple correlators. Search range of the Doppler frequency is reduced by using INS velocity and the number of cells at one search can be increased by using multiple correlators. By using both multiple correlators and the INS velocity in the acquisition, search space can be greatly reduced. Experimental results show that the method gives faster signal acquisition performance than the conventional method.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.51 no.2
• /
• pp.178-186
• /
• 2018

A chirp-echo data acquisition and processing system was developed for use as a simplified, PC-based chirp echo-sounder with some data processing software modules. The design of the software and hardware system was implemented via a field-programmable gate array (FPGA). Digital signal processing algorithms for driving a single-channel chirp transmitter and dual-channel receivers with independent TVG (time varied gain) amplifier modules were incorporated into the FPGA for better real-time performance. The chirp-echo data acquisition and processing system consisted of a notebook PC, an FPGA board, and chirp sonar transmitter and receiver modules, which were constructed using three chirp transducers operating over a frequency range of 35-210 kHz. The functionality of this PC-based chirp echo-sounder was tested in various field experiments. The results of these experiments showed that the developed PC-based chirp echo-sounder could be used in the acquisition, processing and analysis of broadband acoustic echoes related to fish species identification.

• Proceedings of the Technology Innovation Conference
• /
• 1999.06a
• /
• pp.98-118
• /
• 1999

This study deals with the knowledge acquisition activities along the growth stages of Korean ventures. This issue is very important in the three reasons. First, the target of the study-new ventures- is a pending issue and can be regarded as the engine of innovation in the Korean economy. Second, venture activities is so dynamic compared to those of the established companies and the study reflects its dynamic features. Third, the knowledge is becoming more important one among various resources, and knowledge management can be a timely issue. The main research questions are as follows : - How does the degree of knowledge domain, vary along the growth stages\ulcorner - Which knowledge domains are more influential on the performance along growth stages\ulcorner Major findings of the study are as follow: First, technological knowledge acquisition effort are most intensive at the start-up stage, while the management knowledge efforts are active at the growth stage. The degree of market knowledge acquisition efforts is almost the same along the stages. Second, the important knowledge domain, which influences on the performance, varies along the stages. The acquisition effort for product technology knowledge is more influential on the sales growth rate and has a negative effect on the return on assets at the start-up stage, while the management knowledge about administration is more influential on the return on assets at the growth stage. Finally the academic contributions and managerial implications of the study are presented and the future research directions are also suggested.