• The Journal of the Korea Contents Association
• /
• v.16 no.5
• /
• pp.104-112
• /
• 2016

The Adaboost chooses a good set of features in rounds. On each round, it chooses the optimal feature and its threshold value by minimizing the weighted error of classification. The involved process of classification performs a hard decision. In this paper, we expand the process of classification to a soft fuzzy decision. We believe this expansion could allow some flexibility to the Adaboost algorithm as well as a good performance especially when the size of a training data set is not large enough. The typical Adaboost algorithm assigns a same weight to each training datum on the first round of a training process. We propose a new algorithm to assign different initial weights based on some statistical properties of involved features. In experimental results, we assess that the proposed method shows higher performance than the traditional one.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.6
• /
• pp.87-92
• /
• 2013

This paper focuses on analyzing the effects of primary user (PU) signal arrival on the local spectrum sensing performance. The probability for signal arrival at a sample in the sensing time is uniformly distributed in the sensing time. We first analyze the main factor that causes the degradation in the detection results in the conventional energy detection (CED) under the uniformly random arrival of the PU-signal. Thus we propose an approach in order to enhance the detection performance, in which an estimator which detects the arrival of the PU signal cooperates with a composite energy detection. The mathematical analysis and numerical simulation has validated the outperformance of the proposed approach compared to the CED.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.3
• /
• pp.79-84
• /
• 2011

In this paper, we analyzed performance of vehicle detection for ITS (Intelligent Transport System) applications. We simulated the vehicle detection at Hi-Pass System is based on DSRC (Dedicated Short Range Communication). DSRC is a wireless network using ITS, including GPS (Global Positioning System) satellites in conjunction with the national transportation system. The system performance is evaluated in terms of bit error probability. In the simulation, the vehicle speed is set at 60 km/h and carrier frequency is 5.8 GHz. Wireless channel is modeled as the Rician fading channel. In the transmitter, the ASK (amplitude shift keying) modulation scheme is applied. From simulation results, we confirmed that performance of applied Alamouti scheme is better than other systems.

• The KIPS Transactions:PartB
• /
• v.12B no.7 s.103
• /
• pp.721-728
• /
• 2005

This paper suggests effective object detection system for moving objects with specified color and motion information. The proposed detection system includes the object extraction and definition process which uses MCN(Multiple Color Normalization) and MCWUPC(Moving Color Weighted Unmatched Pixel Count) computation to decide the existence of moving object and object segmentation technique using signature information is used to exactly extract the objects with high probability. Finally, real time detection system is implemented to verify the effectiveness of the technique and experiments show that the success rate of object tracking is more than $89\%$ of total 120 image frames.

• Korean Journal of Optics and Photonics
• /
• v.12 no.2
• /
• pp.71-76
• /
• 2001

We studied quantum cryptography based on the quantum nature of light. We must reduce the intensity of the light pulse to the single photon regime for quantum cryptographic communication. Considering the noise and the quantum efficiency of the detector, however, we have to fmd a criterion for which we are able to distinguish the error caused by eavesdropping from other system noises. By changing the bias voltage of the detector and the threshold of the signal voltage, we find the safe region for which we can distribute the quantum key with positive proof of no-eavesdropping. The quantum key we used is a four state quantum key (BB84). BB84).

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.04a
• /
• pp.836-839
• /
• 2012

본 논문에서는 운전자의 안전을 보장하기 위해 영상 처리 기술을 기반으로 도로 정보를 검출해 운전자에게 알려주고, 버튼을 직접 손으로 눌러야 하는 물리적 인터페이스를 대체할 차세대 인터페이스 기술을 제안한다. 제안된 기술은 카메라 한대에서 입력 받은 영상 정보를 제안된 알고리즘을 통해 앞차와의 거리, 차선, 교통 표지판을 검출하고 차량 내부를 주시하는 카메라와 운전자의 음성을 인식할 마이크를 기반으로 음성인식과 동작 인식이 결합된 인터페이스를 제공한다. 본 논문에서 개발된 기술을 통해 설제 테스트를 실시해 본 결과 표지판인식, 차선검출, 앞차와의 거리 검출 등의 인식률이 약 90% 이상이었으며, 이러한 기술적 요소들은 운전자가 인지하지 못하는 상황 등에서도 적절한 정보를 운전자에게 제공해 줌으로써 교통사고 확률을 크게 낮출 수 있을 것으로 기대된다.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.42 no.12
• /
• pp.79-90
• /
• 2005

In this paper, we propose a new clustered reconfigurable interconnect network (CRIN) BIST to improve the embedding probabilities of random-pattern-resistant-patterns. The proposed method uses a scan-cell reordering technique based on the signal probabilities of given test cubes and specific hardware blocks that increases the embedding probabilities of care bit clustered scan chain test cubes. We have developed a simulated annealing based algorithm that maximizes the embedding probabilities of scan chain test cubes to reorder scan cells, and an iterative algorithm for synthesizing the CRIN hardware. Experimental results demonstrate that the proposed CRIN BIST technique achieves complete fault coverage with lower storage requirement and shorter testing time in comparison with the conventional methods.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.5A
• /
• pp.450-456
• /
• 2011

In this paper, idle channel search schemes based on spectrum sensing are proposed for cognitive radio systems with multiple channels. Specifically, we propose a scheme for determining the order of sensing for multiple channels, for which the probability of each channel being idle is estimated every search interval. By performing sensing in the descending order of the probabilities, the time required for searching idle channels is expected to decrease. In addition, we combine the proposed scheme with a user grouping scheme to further improve the sensing performance. Simulation results show that the user grouping reduces the search time, although it degrades the reliability of detection. The proposed search scheme based on probability estimation of channel idleness is found to reduce the search time significantly as compared to the conventional random search scheme. We apply both the proposed search scheme and user grouping scheme to a cognitive radio system to validate the overall performance.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.20 no.2
• /
• pp.35-40
• /
• 1983

The bit error probability of PCM/FM system was derived and numerically calculated. Binary NRZ-L baseband signal was premodulation filtered to frequency modulate a sinusoidal carrier, and a common circuit of limiter-discriminator was employed as a detector. Considering both RF spectrum limitation and bit error Probability reduction, it was found that h ≒ 3WT would be reasonable, where h is the frequency deviation ratio, W is the bandwidth of a premodulation filter and T is the time interval of one bit.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.1
• /
• pp.152-159
• /
• 2005

For high-speed data communication in band-limited channels, main of the bit error are fading and ISI(Inter-Symbol Interference). The common way of dealing with ISI is using equalization in the receiver. In this thesis, channel adaptive equalizer which uses Fuzzy Stochastic Gradient(FSG) and Constant Modulus Algorithm(CMA) is nonlinear equalizer, or Blind equalizer, that works directly on the signals with no training sequences required. This equalizer employs Takagi-Sugeno's fuzzy model that uses the FSG algorithm, to automatically regulate the step size of the descent gradient vector, combining fast convergence rate and low mean square error(MSE), and the CMA which is a special case of Godard's algorithm, to having multiple dispersion constants($R_p$).