Earticle

본 논문에서는 타겟의 RCS Calibration의 정확도를 향상시키기 위해 Time-Gating 조건에 대한 최적화 기법을 제안하였다. Matlab 기반의 코드를 이용하여 RCS Calibration의 최적화 코드를 개발하였으며, 그 조건을 찾기 위해 S-Parameter 신호 처리 알고리즘을 제시하였다. 안테나와 Far-field 조건을 만족한 거리에 있는 타겟 을 두고 측정실험을 진행하였다. 제안하는 신호 최적화 방법의 핵심은 실험에서 측정된 시간 도메인 S-Parameter 값을 확인하여 폭과 레퍼런스 포인트를 조절하는 것이다. 그 방법의 적용 과정을 본 논문에서 서술하였으며, 시간 축에서의 S21의 신호를 확인하여 타겟의 위치를 기준으로 한 Time-Gating 최적화를 진행하였다. 결과적으로 게 이팅 최적화 코드를 적용하였을 때 최적화가 진행되지 않았을 경우와 비교하여 약 12배만큼 정의된 에러 값이 감 소함을 확인할 수 있었다.

In this paper, an optimization technique for time-gating conditions is proposed to improve the accuracy of target RCS calibration. An RCS calibration optimization code was developed using Matlab-based code, and an S-Parameter signal processing algorithm was presented to find the condition. The measurement experiment was conducted with the antenna and the target at a distance that satisfies the far-field condition. The signal optimization method is to check time domain S-parameter value measured in the experiment and adjust the width and reference point. The process of applying the method was described in this paper, and time-gating optimization was performed based on the position of the target by checking the signal of S21 on the time axis. As a result, when the gating optimization code was applied, it was confirmed that the defined error value was reduced by about 12 times compared to the case where optimization was not performed.

Many studies are being conducted to implement wireless charging, for example, for cellular phones or electronic tooth brushes, via wireless power transmission technique. However, the magnetic induction method had a very short transmission distance. To solve this problem, the team of Professor Marin Soljacic proposed a magnetic resonance system that used two resonance coils with the same resonance frequency. It had an approximately 40% efficiency at a 2m distance. The system improved the low efficiency and short distance problems of the existing systems. So it could also widen the application range of wireless power transmission. Many studies on the subject are underway. In this paper, the superconductor coil was used to improve the efficiency of magnetic resonance wireless power transmission. The resonance wireless power transmission system had a source coil, a load coil, and resonance coils (a transmitter and a receiver). The efficiency and distance depended on the characteristics of the transmitter and receiver coils that had the same resonance frequency. Therefore, two resonance coils were fabricated by superconductors. The current density of the superconductor was higher than that of the normal conductor coil. Accordingly, it had a high quality-factor and improved efficiency

본 논문은 S-파라미터를 어드미턴스 파라미터로 변환하는 것을 바탕으로 비대칭 분배되면서 동시에 임의의 임피던스로 변환시킬 수 있는 임피던스 변환기를 나타내었다. 회로 해석 방법을 우수/ 기수 모드 방법과 비교하면 본 논문의 파라미터 변환을 통한 방법은 위상 지연 정보와 임의의 포트 임피던스 값을 포함시키고 그리고 비대칭 구조등을 해석하는데 간단함을 알 수 있다. 이 설계 방법의 타당성을 확인하기 위해서 중심주파수 1 GHz에서 3:1의 비대칭 분배비율을 갖고 있고 $50{\Omega}$을 $12.5{\Omega}$ 비율로 변환되는 임피던스 변환기를 설계하였다. 임피던스 변환기를 구현하는 방법은 유도된 수식으로부터 계산된 작은 임피던스 선로를 병렬 오픈스터브가 연결된 전송선로를 사용하여 구현하였고, 이것의 실험 결과는 시뮬레이션 결과와 동일하게 나옴을 확인하였다.

This paper presents an arbitrary impedance transformer with unequal split, based on S- to admittance parameter conversion. When compared even/ odd- mode analysis, the parameter conversion design method constitutes a simple design method to include phase delay information and arbitrary port impedances and asymmetrical configurations. To validate this design method, we designed a 50 to $12.5{\Omega}$ impedance transformer with a 3:1 unequal power split, at an operating frequency of 1 GHz. To implement the proposed impedance transformer, the low impedance transmission lines of calculated result are fabricated by the transmission line connected shunt open stub. Good experimental performances were obtained, in full agreement with simulated results.

The damping force is determined by four valves and the components which consist of the shock absorber for vehicle. In this study it is investigated the individual effects of four valves and these components on damping forces using dynamic behaviour analysis program of the shock absorber. In addition, opening of main valves are researched during compression and tension cycle due to up- down reciprocation movement of piston. We are to strictly control the properties and tolerance of componenets having important effects on the damping force. Thus we are intended to produce shock absorber of better quality.

Recently the incidence of rollover accidents has increased due to the increase of SUV, and the probability of occupant injury in rollover accidents is very high, so research is needed accordingly. In this study, PC-CRASH, which is a program used for traffic accident analysis, is used for checking rollover speed and rollover angle of each situation in case of rollover accident, and applied to design variables of LS-DYNA which is finite element analysis program, so deformation displacements of roof according to collision velocity and angle were derived. Also, it is possible to predict rollover vehicle speed by using the derived value and the measured deformation displacement of roof in actual rollover accident, and it is possible to reconstruct accident more accurately by applying to PC-Crash which is traffic accident reconstruction program, so it is thought that it can be utilized analyzing traffic accident usefully.

이 연구는 학교조직의 갈등발생과 성격특성이 교사의 직무만족도에 미치는 영향을 알아보는데 있다. 이 연구를 통하여 다음과 같은 결론을 얻을 수 있었다. 성격특성은 응답자 빈도가 ‘순응형(77.4%)>공격형(15.6%)>후퇴형(7.0)’ 순이다. 성격특성에 따라 갈등해결방법이 다르게 나타났다. 공격형과 순응형은 ‘협력>적응>타협>회피’이고, 후퇴형은 ‘협력=회피>타협>적응’순이었다. 즉 성격특성과 갈등해결요인 중 순응형으로 ‘협력’요인의 선택비율이 가장 높았다. 직무만족도요인 중 교직관, 인간관계, 인사관계 측면에서 직무만족도가 높았다. 특히‘공격형*타협’요인에서 4.0이상의 높은 직무만족도를 보였다. 성격특성과 조직분위기요인과의 관계에서는 순응형 성격으로 친교적, 인간지향 분위기를 선호하는 경향이 높았다. 직무만족도에서는 순응형 친교적 분위기 일 때가 3.6으로 가장 높고, 후퇴형 방관적 분위기일 때 2.63으로 가장 낮았다. 독립변수와 매개변수와의 각각의 관계는 유의한 차이가 있다. 즉 갈등발생과 성격특성요인과는 후퇴형 성격이 갈등발생이 높고, 순응형 성격이 가장 낮았다. 조직분위기와 갈등해결요인과는 친교적일 때 ‘협력’을 선호하고 방관적일 때 ‘회피’ 선호경향이 높으나 ‘타협’, ‘적응’, ‘협력’을 고루 선택하고 있다.

A teacher is the main which strongly influences on the educational activities, and plays the most important role in the improvement of the students' learning abilities and school atmosphere. Comprehensive consideration on the different kinds of variables is needed to understand which variables are related with the teachers' job satisfaction. Thereby, a study was conducted on the relation between independent variables which are conflict occurrence and personality traits influencing job satisfaction, and parameters which are conflict solution and group atmosphere. The following results were came out through this study. The answers of personality traits turned out to be 'adaptable(77.4%)', 'aggressive(15.6%)', 'regressive(7.0)' in order of frequency. Conflict-solving ways turned out to be different according to the personality traits. 'Aggressive' and 'adaptable' traits have 'cooperation', 'adaptation', 'compromise' and 'avoidance', and 'regressive' has 'cooperation' and 'avoidance' at a same level, 'compromise' and 'adaptation' in order of frequency. That is, the preference of 'cooperation' for 'adaptable' among personality traits and conflict-solving factors was highest. Job satisfaction appeared most in the aspects of views on teaching, human relationship and promotion. Especially, job satisfaction on the factors of 'aggressive*compromise' appeared over 4.0. The high preference for friendly and humane atmosphere in 'adaptable' appeared related with personality traits and group atmosphere. Job satisfaction turned out to be 3.6 at its highest in adaptable and friendly atmosphere, and 2.63 at its lowest in regressive and onlooking atmosphere. There are meaningful differences in the relation with independent variables and parameters respectively. That is, in the respect of relation between conflict occurrence and personality traits, 'regressive' caused more conflict and 'adaptable' did least conflict. And in the respect of relation between group atmosphere and conflict-solving factors, 'cooperation' was preferred in friendly mood and 'avoidance' in onlooking mood. However, 'compromise', 'adaptation' and 'cooperation' were chosen impartially.

이 연구에서는 특수경비원의 조직 내 의사소통이 직무만족과 직무몰입에 영향을 미치는데 있어서의 대인관계 능력의 매개효과를 살펴보기 위해 교육시설․공항․교통시설에서 근무하고 있는 특수경비원을 대상으로 2015년 9월 20일부터 2015년 10월 20일까지 설문조사를 실시하였다. 연구의 분석 결과는 다음과 같이 나타났다. 대인관계 능력 매개 효과 분석모형도는 포화모형도이며, 직무만족(직무몰입)에 대한 대인관계 능력의 매개 효과 분석 결과를 살펴보면, 대인관계와 의사소통의 수준이 높을수록 직무만족(직무몰입) 수준이 높게 나타났으며, 또한 대인관계에서 의사소통 수준이 높을수록 대인관계 수준도 높게 나타났다. SMC에서는 직무만족이 23.9%, 직무몰입이 11.6%, 대인관계는 19.3% 설명한다. 또한, 직무몰입에 대한 대인관계 능력의 매개 효과 분석의 결과는 의사소통이 직무만족(직무몰입)에 미치는 영향에 대인관계가 매개효과가 존재함을 확인할 수 있다. 의사소통이 대인관계에 미치는 직접효과는 통계적 유의도가 나타났다. 이 연구의 결과를 종합해 보면, 특수경비원의 조직 내 의사소통이 직무만족과 직무몰입에 영향을 미치는데 대인관계 능력의 매개 효과가 있는 것으로 나타났다.

In this study, the special guard duties and duties within the Organization of communication influence on immersed in the interpersonal skills to discover the effects of the parameters of the educational facilities in the airport traffic facilities, and anything that increases the special guards, September 20-target 2015 2015 October 20 poll. The study compared the results of analysis are as follows. Analyze the effect of model parameter, interpersonal skills are also satisfied with the saturated model, duties (duty immersion) interpersonal skills for the parameters of the effect analysis when you look at the results, the higher the level of communication and interpersonal relationships and job satisfaction, but also high level of (job immersive) interpersonal communication in interpersonal relationships, higher levels are high. SMC, job satisfaction, job commitment 23.9% 7.2%, 19.3% of interpersonal relationships. In addition, the duties of immersive interpersonal skills for the parameters of the effect the results of the analysis of communication and its impact on job satisfaction (duty of immersion) in interpersonal work parameters can verify that it exists. Communication on direct interpersonal relationships, keep in mind that the statistical effect also appeared. If you look at the overall results of this study, special communication organization of job satisfaction and security guard job influence on interpersonal skills immersed the parameters of the effect.

본 논문에서는 밀리미터파 대역에서 다양한 매질들에 대한 유전적 특성의 측정을 통해 유전율 결과를 제시 하였다. 밀리미터파는 짧은 파장과 넓은 대역폭을 가지고 있어 부품의 소형화, 경량화가 가능하고, 정보의 대량 전송 이 가능하다는 장점을 가지고 있기 때문에 그 연구의 필요성이 높아지고 있다. 이 대역의 전파는 직진성이 뛰어나고 회절성이 작으며 여러 물질들에서 전파가 흡수되어 불필요한 간섭이 잘 발생하지 않는 특징을 가지고 있다. 그렇기 때문에 밀리미터파 대역의 전파가 진행하는 과정에서 반사·투과하는 다양한 매질들의 전기적인 특성에 대한 분석이 중요할 것이다. 따라서 본 논문에서는 밀리미터파 대역에서 Free Space 방식을 이용하여 물질의 반사·투과 특성을 측 정하였다. 이를 활용하여 Nicolson-Ross Weir 유전율 계산법을 이용해 다양한 매질들의 유전율을 도출하였다.

This paper presents the results of permittivities of various materials by measurements of the dielectric properties for the materials in millimeter-wave band. Since the advantages of millimeter wave band include the miniaturization, weight reduction of component and a lot of information transfer, its study has received increasing attention of researches. Also, because of the characteristics of the band have the superior straightness and the small diffractive, in the band, the analysis for the reflection and transmission characteristics of the materials will be very important. Moreover, a low interference is one of characteristics of the band due to the fact that the millimeter wave is absorbed in the materials. Therefore, in this paper, the reflection and transmission characteristics of materials are measured in the band by using the free space method. Based on the presented result, the permittivities of the materials are derived by the calculation of Nicolson-Ross Weir method.

The target echo of downward-looking radar can be simulated by a multicomponent Chirp signal with noise, which makes signal detection and parameter estimation a very important processing. Aiming at the problems of error detection caused by the cross-terms in WVD-Hough methods and other modified WVD distribution methods, and low precision due to poor time-frequency concentration in S-Hough transform, this paper proposed a signal detection and parameters estimation algorithm of multicomponent Chirp signals based on generalized S-transform. Firstly calculate the time-frequency distribution of multicomponent Chirp signals by generalized S-transform, then execute Hough transform to the generalized S-transform TFD on the time-frequency plane to implement signal detection and parameter estimation to the multicomponent Chirp signals. The simulation results show that this algorithm has good performance in detection the multicomponent Chirp signals in low SNR case.

본 논문에서는 고장예측진단 및 건전성 관리 기법(Prognostics and Health Management, PHM)을 적용하기 위해 해당 시스템 혹은 회로 내부에서 결함특성을 감지하고 예측할 수 있는 회로 구조를 제안하였다. 기존 연구에서 회로 결함의 진행에 따라, S-parameter 크기 최소값의 주파수가 변화하는 것을 확인하였다. 이러한 특성을 기존에는 네트워크 분석기(Network Analyzer)를 활용하여 측정하였으나, 본 연구에서는 같은 결함검출기법을 활용하더라도 큰 계측장비 없이 결함의 진행상황 및 잔여 수명, 결함발생 여부를 확인할 수 있는 소형화된 회로를 설계하였다. 본 연구에서는 S-parameter의 변화를 야기하는 임피던스의 변화를 감지할 수 있도록 회로를 설계하였으며, Bond-wire의 온도반복에 따른 S-parameter 변화 측정결과를 제안하는 회로에 적용하였다. 이를 통해 해당 회로가 Bond-wire의 결함을 감지할 수 있다는 것을 성공적으로 검증하였다.

In this paper, in order to apply Prognostics and Health Management(PHM) to an electronic system or circuit, a circuit capable of detecting and predicting defect characteristics inside the system or circuit is implemented, and the results are described. In the previous study, we demonstrated that the frequency of the amplitude of S-parameter changed as the circuit defect progressed. These characteristics were measured by network analyser. but in this study, even if the same defect detection method is used, a circuit is proposed to check the progress of the defect, the remaining time, and the occurrence of the defect without large measurement devices. The circuit is designed to detect the change in impedance that generates changes of S-parameter, and it is verified through simulation using the measurement results of Bond-wires.

Measurements of surface resistance ($R_s$) of high temperature superconductor (HTS) films with accuracy are essential for microwave applications of HTS materials. In using the dielectric resonator method, uncertainties in the unloaded quality factor of the resonator cause significant errors in the measured $R_s$ of HTS films. We compare the Rs values of $YBa_2Cu_3O_{7-{\delta}}$ films calculated from the $Q_0$ as determined from the Lorentzian fit with that from the $Q_0$ as determined from the S-parameter circle-fit at temperatures between 15 K and 77 K. The two sets of values appeared to differ by 5%, 7%, 6%, and 11% at temperatures of 15, 60, 70, and 77 K, respectively, from each other, implying that careful error analysis needs to be performed in obtaining the $R_s$ of HTS films by using the Lorentzian-fit method, with the ones determined from the S-parameter circle-fit used as the reference.

Accurate measurements of the microwave surface resistance (Rs) of high temperature superconductor (HTS) films are important with regard to applications of HTS materials for wireless communications. As the surface resistance values of HTS films are usually extracted from the measured unloaded quality factor ($Q_0$) of resonators made of HTS films, it is essential to measure the resonator $Q_0$ with accuracy. The $TE_{011}\;mode\;Q_0$ of sapphire resonators with the endplates made of $YBa_2Cu_3O_{7-{\delta}}$(YBCO) film on $LaAlO_3$ is measured by using the S-parameter circle-fit method at a frequency of about 19.6 GHz and temperatures of 30 K to 90 K, which is compared with the measured values by using the Lorentzian-fit method. Good agreements are found between the two sets of $Q_0$ values measured by using the two different methods whether the resonator is used in a weak-coupling scheme or a strong-coupling scheme, showing reliability of both methods fur measuring the resonator $Q_0$ accurately. The $Q_0$ of sapphire resonators with a gap between the top plate and the rest of the resonator is also discussed.

본 연구는 S-parameter를 이용한 변압기의 고주파 모델링 방법을 제시한다. 1차측과 2차측을 단락 또는 개방 회로를 구성하여 각 상태에서의 반사계수를 Vector Network Analyzer로 측정하였다. 측정 결과로부터 등가회로 소자를 추출하여 고주파 등가회로를 모델링하고, 2-port 회로에서 측정한 S-parameter 측정치와 시뮬레이션 결과를 비교함으로써 타당성을 검증하였다. 이는 정확하고 예측 가능한 고주파 변압기를 설계하는데 적용될 수 있다.

In this paper, we propose a method for high-frequency modeling of transformers using the S-parameter. The open and short circuits of the primary and secondary sides were configured, and the reflection coefficient in each circuit was measured using a vector network analyzer. The equivalent circuit elements were extracted from the measured results to model the high-frequency equivalent circuit, and the validity of the method was verified by comparing the measured S-parameters in a 2-port network with the simulation results.

본 연구에서는 MRAM(magnetic random access memory)이 10 GHz까지 높은 주파수에서 동작할 때 쓰기 신호와 읽기 신호가 얼마나 효율적으로 전달되는지 계산하였다. 이를 위해 읽기와 쓰기에 필요한 도선이 있는 시편을 3차원으로 모델링하였다. 모의실험은 쓰기 동작과 읽기 동작으로 나눠서 수행되었고, FEM(finite element method) 알고리즘을 이용하여 S-parameter를 출력하였다. 계산된 결과를 이용하여 실험적으로 설계된 MRAM 시편의 쓰기와 읽기 동작에서 전송계수 S$_{21}$을 각각 DC에서 1 GHz 그리고 100 GHz 까지의 영역에서 해석하였다. 또한 각각의 길이가 600 $\mu$m인 bit line과 sense line사이의 절연체 두께를 500에서 1500$\AA$으로 변화시켰을 때, 3 dB 감쇄 주파수를 135에서 430 MHz까지 약 3.3배 높일 수 있었다. 그리고 계산된 S-parameter를 이용하여 전달 지연을 계산하여 접근시간을 예측하였다.

In this work, transmission characteristics of read and write signal were calculated when a MRAM (magnetic random access memory) cell is operated up to 10 GHz. Test device having long read and write lines was modeled in 3 dimensions to perform a simulation. The simulation was divided into two parts, read and write operations, and S-parameters were computed utilizing FEM (finite element method) algorithm. Transmission coefficients, S$\sub$21/, for read and write operations of MRAM device which was designed for a single cell test configuration were analyzed from DC to 1 GHz and DC to 10 GHz, respectively. When the insulator thickness between the bit and sense lines was increased from 500 to 1500 ${\AA}$, 3 dB attenuation frequency was increased by 3.3 times, from 135 to 430 MHz. The length of the bit and sense lines were 600 ${\mu}$m. In addition, access time was estimated by calculating the propagation delay utilizing S-parameters.

The conjugate gradient method is well-known for its very low memory requirements, as it does not need to compute or store large matrices. It remains a popular choice among researchers addressing large-scale optimization problems. In this paper, we propose a modified conjugate gradient approach based on Perry's conjugate gradient parameter combined with a logistic mapping formula. Furthermore, we apply the new method to neural network training. The proposed algorithm satisfies key theoretical properties, including descent conditions, sufficient decrease, and global convergence guarantees. Numerical experiments demonstrate that our novel conjugate gradient method outperforms classical methods such as Perry's method in terms of efficiency and competitiveness. The performance comparison is conducted using a set of common benchmark problems of varying dimensions, with evaluation metrics including the total number of function evaluations and iterations. Additionally, the effectiveness of the proposed method is validated through numerical results on neural network training for trigonometric function approximation.

In this study, the effects of the frequency-dependent characteristics of through-silicon vias (TSVs) on the performance of 3D ICs are examined by evaluating a typical interconnection structure, which is composed of 32-nm CMOS inverter drivers and receivers connected through TSVs. The frequency-domain model of TSVs is extracted in S-parameter from a 3D electromagnetic (EM) method, where the dimensional variation effect of TSVs can be accurately considered for a comprehensive parameter sweep simulation. A parametric analysis shows that the propagation delay increases with the diameter and height of the TSVs but decreases with the pitch and liner thickness. We also investigate the crosstalk effect between TSVs by testing different signaling conditions. From the simulations, the worst signal integrity is observed when the signal experiences a simultaneously coupled transition in the opposite direction from the aggressor lines. Simulation results for nine-TSV bundles having regular and staggered patterns reveal that the proposed method can characterize TSV-based 3D interconnections of any dimensions and patterns.

According to the so-called 'NP/DP parameter,' languages with articles may project both DP and NP in the nominal domain, while those without can have at most NP with the DP layer missing (Fukui (1988), Chierchia (1998), Boskovi? (2008), inter alia). Recently, extending this line of reasoning to the clausal domain, Boskovi? (2010) argues that article-less languages, such as Hindi, Japanese, Korean and Turkish, do not have TP in the clausal architecture. This paper aims to closely examine whether Boskovi?'s claim, referred to as 'TP parameter,' is tenable. We show that careful reconsideration of TP parameter is required since it undergenerates: i.e., there are a number of empirical data in Korean, an article-less language, which it wouldn't be easy to explain unless TP is postulated. The data revealing problems for the parameter include (i) the dependency of licensing negation upon TP in key-ha-la imperatives; (ii) the availability of sentential negation and a verbal predicate in a resulting clause in resultatives; and (iii) the asymmetry between clausal ellipsis and replacement of the pro-form kulehkey.