• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.4
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• pp.435-442
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• 2010

The efficiency of the car's wiper blade has a great contribution to the guarantee of security. To guarantee the wiper blade's ability of getting rid of dust sticking on the glass surface, the qualities of lubricant, durability, heat resistant, low temperature, ozone resistant, chemical resistant must be good as well as it being noiseless. Like this, in order to improve the wiper's skills, it is essential to have a system that is able to assess and analyse the properties of the wiper. In this paper, to create a system that measures the car's wiper pressure, an analog/digital converter (ADC) that receives signals generated from the pressure sensor and transmits it to a personal computer is proposed. The designed ADC is one of the pipeline ADCs that can obtain fast movement rate and also a structure that can optimize the entire system's area as well as the consumption of strength.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1171-1180
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• 2019

Emotion is a psycho-physiological process that plays an important role in human interactions. Affective computing is centered on the development of human-aware artificial intelligence that can understand and regulate emotions. This field of study is also critical as mental diseases such as depression, autism, attention deficit hyperactivity disorder, and game addiction are associated with emotion. Despite the efforts in emotions recognition and emotion detection from nonstationary, detecting emotions from abnormal EEG signals requires sophisticated learning algorithms because they require a high level of abstraction. In this paper, we investigated LSTM hyperparameters for an optimal emotion EEG classification. Results of several experiments are hereby presented. From the results, optimal LSTM hyperparameter configuration was achieved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.1-7
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• 2016

In this paper, the compact CPW-fed slot antenna for WLAN applications is proposed. While the proposed antenna with size of only $20{\times}18{\times}1mm^3$ is consisted of double stub and folded slot, the antenna for 2.4 GHz band and 5 GHz band is designed and fabricated with optimized parameters obtained by simulation. Proposed antenna is fabricated with FR-4 substrate to the thickness of 1.0 mm. By obtaining the measured return loss level of < -10 dB at dual-band, we showed that it is operated as antenna for WLAN applications, and then it is also expected to be usable as antenna for RFID.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.151-161
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• 2011

PGA(Phase Gradient Autofocus) is a representative autofocus technique to improve the SAR(Synthetic Aperture Radar) image quality. PGA can estimate high order phase errors and have good robustness in noisy environments. However, PGA is not suitable to apply to the stripmap mode data directly because it is based on the spotlight mode operation. In this paper, the PGA implementation technique for stripmap mode data and the method of ROI(Region of Interest) selection that affects severely on PGA performance have been proposed. The proposed technique was verified by the point target simulation first, and was applied to the real SAR signal data acquired by the flight test. Finally, the significant improvements in focusing quality were shown in the processed SAR images using the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.623-629
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• 2002

The spectrum of impulse response signal from an impulse hammer testing is widely used to obtain frequency response function(FRF) of the structure. However the FRFs obtained from impact hammer testing have not only leakage errors but also finite record length errors when the record length for the signal processing is not sufficiently long. The errors cannot be removed with the conventional signal analyzer which treats the signals as if they are always steady and periodic. Since the response signals generated by the impact hammer are transient and have damping, they are undoubtedly non-periodic. It is inevitable that the signals be acquired for limited recording time, which causes the finite record length error and the leakage error. In this paper, the errors in the frequency response function of multi degree of freedom system are formulated theoretically. And the method to remove these errors is also suggested. This method is based on the optimization technique. A numerical example of 3-dof model shows the validity of the proposed method.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.65-76
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• 2004

교통망설계문제란, 교통시스템을 최적상태로 만들기 위한 최적의 설계변수를 결정하는 문제이다. 대표적인 교통망설계문제로는 도로를 신설하거나 확장하는 문제가 있으며, 이외에 교통신호시간의 결정, 교통정보의 제공, 혼잡통행료 부과, 새로운 교통수단의 도입 등 여러 교통정책분야가 교통망설계문제에 포함된다고 볼 수 있다. 일반적으로 교통망설계문제는 bi-level 구조로 구축되는데, 기존 대부분의 연구들은 상위문제와 하위문제를 서로 협력없이(Noncooperative) 자신들만의 목적을 최적화시키는 Cournot-Nash게임형태로 구성하여 풀고 있으나, 실제 교통분야에서 다루는 문제들은 리더(leader)와 추종자(follower)가 존재하는 Stackelberg게임에 가깝다고 할 수 있다. 기존 bi-level 문제들이 Cournot-Nash게임형태로 구성되어 풀고 있는 이유는 Stackelberg게임으로 구성할 경우 풀기가 어렵기 때문이다. 이런 측면에서 본 연구는 리더와 추종자가 존재하는 Stackelberg게임으로 교통망설계문제를 구성하며, 설계 변수값에 따른 통행자의 행태변화도 인지오차(perceived error)를 고려한 확률적 통행배정문제로 구성하여 좀더 현실적인 결과를 도출하도록 한다. 제시된 모형을 풀기 위하여 민감도분석(Sensitivity analysis)을 이용하며, 설계문제의 해를 구하는 알고리듬도 제시한다. 또한, 이 기법을 일반 도로교통망(general transportation road network)에 적용할 수 있도록 민감도(sensitivity) 유도과정을 자세히 기술하였다. 개발된 모형을 평가하기 위하여 2개의 예제 교통망을 대상으로 모형을 적용한 결과, 합리적인 값들을 도출하고 있음을 확인할 수 있었다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.48-56
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• 2005

Predictive filter theory proposed recently can be characterized by inherent advantages of estimating modelling error and overcoming the disadvantage of the Kalman filter theory. A one-step ahead error is minimized to produce optimized filter performance in the form of the predictive filter. The main advantage of this filter lies in the ability to estimate both state vector and system model error. In this paper, attitude estimation results based upon the predictive filter theory is addressed. Mathematical formulation for estimating bias signal is peformed by using the predictive filter theory, and attitude estimation based upon vector observation is presented. From the results of this study, the potential applicability of the predictive filter is highlighted.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.410-414
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• 1997

Laser projection display is a full color display system for large area. In this system, laser beams are modulated at acousto optic modulators(AOM) according to the video signal. AOM consists of a $TeO_2$ crystal and a $LiNbO_3$ transducer. We calculated the acoustic wave propagating from transducer to acousto optic media and made AOM by the calculated results. We compared calculated results with fabricated AOM by measuring modulation efficiency at various frequency. The modulation efficiency of AOM is 85% at the carrier frequency of 144MHz and the rise time is 41.5 ns.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.370-376
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• 2011

Recently, the application range of plastic gears is widely expanding by the development of engineering plastics with good mechanical properties. Plastic gears have excellent performances such as light weight, water resistance and vibration absorbing ability for metallic gears. In this study, the optimization of injection molding process was done for the large disk type plastic gears of auto phoropter. Design Of Experiment (Taguchi method) was adopted to find a tendency of molding conditions that influence the flatness of disk type gear. Four main factors for molding conditions were selected based on injection temperature, filling time, packing pressure and mold temperature. Also, Filling, packing and cooling analyses were carried out to evaluate Z directional deflection of large disk type gear by using the simulation software (Moldflow) based on the DOE. From the results, it was found that the injection temperature and packing pressure are the most sensitive parameters for the Z directional deflection of large disk type gears.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.4
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• pp.47-52
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• 2005

In this paper, the genetic algorithm is used to design a fixed order square decoupling $H_{\infty}$ controllers based on the Two-Degree-of-freedom standard model. The proposed decoupling $H_{\infty}$ controller which is minimizes the maximum energy in the output signal is designed to reduce the coupling properties between the input/output variables which make it difficult to control a system efficiently. A minimal set of assumptions for existence of the decoupling controller formula is described in the state-space formulas. It is verified by an example.