• 대한의용생체공학회:의공학회지
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• 제42권4호
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• pp.186-192
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• 2021

In this paper, we evaluated prediction accuracy of Euler angle spectrograph classification method using a convolutional neural networks (CNN) for hand gesture recognition in augmented reality (AR) cognitive rehabilitation system based on Leap Motion Controller (LMC). Hand gesture recognition methods using a conventional support vector machine (SVM) show 91.3% accuracy in multiple motions. In this paper, five hand gestures ("Promise", "Bunny", "Close", "Victory", and "Thumb") are selected and measured 100 times for testing the utility of spectral classification techniques. Validation results for the five hand gestures were able to be correctly predicted 100% of the time, indicating superior recognition accuracy than those of conventional SVM methods. The hand motion recognition using CNN meant to be applied more useful to AR cognitive rehabilitation training systems based on LMC than sign language recognition using SVM.

• 문화기술의 융합
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• 제9권3호
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• pp.451-459
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• 2023

이 글의 목적은 새로운 전쟁의 영역으로 떠오르고 있는 인지전(Cognitive Warfare)에서 제기될 수 있는 윤리적 문제를 평가하는 데 있어 정의전쟁론(Just War Theory)의 한계를 규명하는 것이다. 이를 위해 먼저 우리는 인지전이 등장하게 되는 배경을 설명하고 인지전에 대한 개념적 분석을 통해 인지전의 특성을 도출하여 인지전이 전통적 전쟁과 어떠한 차이점이 있는지를 제시할 것이다. 이후 논의를 전환하여 전쟁에 관한 포괄적 윤리적 문제를 평가하는 이론으로서 정의전쟁론의 배경과 주요 논의 영역을 살펴볼 것이다. 이어서 우리는 이이론을 구성하는 3가지 영역인 전쟁 자체의 도덕(jus ad bellum), 전쟁 수행의 도덕(jus in bello), 전쟁 후의 도덕(jus post bellum)에서 제시하는 윤리적 판단 기준을 구체화하고 각 영역에서 제시되는 기준을 인지전의 양상에 적용할 것이다. 마지막으로 우리는 각 영역별로 인지전에서 윤리적 판단의 적절성을 평가하고 정의전쟁론의 윤리적 판단 기준이 적용될 수 없는 영역을 제시함으로써 인지전에 적용할 수 있는 새로운 윤리적 평가 기준의 필요성을 제기할 것이다.

• 공학교육연구
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• 제17권5호
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• pp.8-12
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• 2014

Women in engineering subject were developed for women included engineering education in Korea. Women in the predominantly male-oriented college of engineering which is afflicted by the high dropout rate and the low employment rate of coeds in their majoring fields because of the die-hard male dominant culture. In order to resolve the related problems, Our University has been actively engaged in a movement called "Women into Engineering" (WIE) to raise the gender cognitive awareness and to train women engineers for highly qualified work force. As part of the movement, a subject called "Women in Engineering" that focuses on the gender cognitive perspective is effective to reduce the dropout rate and to land a job inside their fields by stimulating their interest in their specialty made soft/hard skills. The study was conducted a survey of the coeds who have completed the "Women in Engineering" course to evaluate the degree of satisfaction perceived, and a t-test through comparing the group of the coeds and a group of coeds who have not taken the course. The results showed statistically significant responses indicating that both groups of coeds would like to see WIE offer more basic engineering courses like "Women in Engineering." This may lay the foundation to offer other major engineering courses for juniors and seniors that emphasize the gender cognitive approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권8호
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• pp.2675-2690
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• 2014

We study the problem of optimal opportunistic spectrum access with unknown and heterogeneous channel dynamics in cognitive radio networks. There is neither statistic information about the licensed channels nor information exchange among secondary users in the respective systems. We formulate the problem of maximizing network throughput. To achieve the desired optimization, we propose a win-shift lose-stay algorithm based only on rewards. The key point of the algorithm is to make secondary users tend to shift to another channel after receiving rewards from the current channel. The optimality and the convergence of the proposed algorithm are proved. The simulation results show that for both heterogeneous and homogenous systems the proposed win-shift lose-stay algorithm has better performance in terms of throughput and fairness than an existing algorithm.

• Journal of electromagnetic engineering and science
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• 제12권1호
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• pp.1-7
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• 2012

In this paper, we investigated the throughput of a cognitive radio network where two primary frequency channels (PCs) are sensed and opportunistically accessed by N secondary users. The sharing sensing member (SSM) protocol is introduced to sense both PCs simultaneously. According to the SSM protocol, N SUs (Secondary User) are divided into two groups, which allows for the simultaneous sensing of two PCs. With a frame structure, after determining whether the PCs are idle or active during a sensing slot, the SUs may use the remaining time to transmit their own data. The throughput of the network is formulated as a convex optimization problem. We then evaluated an iterative algorithm to allocate the optimal sensing time, fusion rule and the number of members in each group. The computer simulation and numerical results show that the proposed optimal allocation improves the throughput of the SU under a misdetection constraint to protect the PCs. If not, its initial date of receipt shall be nullified.

• Journal of information and communication convergence engineering
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• 제9권3호
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• pp.251-255
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• 2011

In this paper, we investigate an adaptive cognitive radio (CR) scheme where a sensing duration and a detection threshold for spectrum sensing are adaptively determined according to the channel condition in a fading channel. We optimize the sensing duration and detection threshold of a secondary user to maximize the performance of the secondary user guaranteeing a primary user's secure communication. In addition, we analyze the effect of channel fading on the optimization of the sensing duration and detection threshold. Our numerical results show that the performance of the adaptive CR scheme can be drastically improved if a secondary user can take the advantage of channel information between primary and secondary users.

• Journal of Information Processing Systems
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• 제10권3호
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• pp.459-470
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• 2014

In this paper, the average probability of the symbol error rate (SER) and throughput are studied in the presence of joint spectrum sensing and data transmission in a cognitive relay network, which is in the environment of an optimal power allocation strategy. In this investigation, the main component in calculating the secondary throughput is the inclusion of the spatial false alarms, in addition to the conventional false alarms. It has been shown that there exists an optimal secondary power amplification factor at which the probability of SER has a minimum value, whereas the throughput has a maximum value. We performed a Monte-Carlo simulation to validate the analytical results.

• Journal of information and communication convergence engineering
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• 제9권1호
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• pp.27-31
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• 2011

This paper describes the optimization of spectrum sensing in terms of the throughput of a cognitive radio (CR) system. Dealing with the optimization problem of spectrum sensing, this paper evaluates the throughput of a CR system by considering such situations as the penalty time of a channel search and incumbent user (IU) detection delay caused by a missed detection of an incumbent signal. Also, this paper suggests a serial channel search scheme as the search method for a vacant channel, and derives its mean channel search time by considering the penalty time due to the false alarm of a vacant channel search. The numerical results suggest the optimum sensing time of the channel search process using the derived mean channel search time of a serial channel search in the case of a sensing hardware structure with single radio frequency (RF) path. It also demonstrates that the average throughput is improved by two separate RF paths in spite of the hardware complexity of an RF receiver.

• Journal of information and communication convergence engineering
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• 제13권2호
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• pp.74-80
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• 2015

In cognitive radios, spectrum sensing plays an important role in accurately detecting the presence or absence of a licensed user. However, the intervention of malicious users (MUs) degrades the performance of spectrum sensing. Such users manipulate the local results and send falsified data to the data fusion center; this process is called spectrum sensing data falsification (SSDF). Thus, MUs degrade the spectrum sensing performance and increase uncertainty issues. In this paper, we propose a method based on the Hausdorff distance and a similarity measure matrix to measure the difference between the normal user evidence and the malicious user evidence. In addition, we use the Dempster-Shafer theory to combine the sets of evidence from each normal user evidence. We compare the proposed method with the k-means and Jaccard distance methods for malicious user detection. Simulation results show that the proposed method is effective against an SSDF attack.

• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.391-395
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• 2011

Cognitive radio (CR) technique is a useful tool for improving spectrum utilization by detecting and using the vacant frequency bands while avoiding interference to the primary user. The sensing performance in a CR network can be improved by allowing some CR users to perform cooperative spectrum sensing. In this paper, we propose a new sensing algorithm that utilizes an adaptive energy threshold for cooperative spectrum sensing in which a changeable energy threshold is adopted by the CR users for improving local sensing performance. Through the proposed scheme, the reliability of global decision can be enhanced mainly due to the improvement in local sensing performance.