• 한국전기전자재료학회논문지
• /
• 제17권6호
• /
• pp.598-601
• /
• 2004

A microstrip filter has been designed and fabricated in hairpin form on a GaAs substrate and its characteristics such as the insertion loss, return loss, and bandwidth have been investigated. The presented filter is realized with relatively small size, 4.5 by 3.6 mm. The insertion loss and return loss of the filter are 1.17 dB and 30 dB, respectively. The filter exhibits 3 dB-bandwidth of 350 MHz at the center frequency, 5.890 GHz. The experimental results show good agreement with the numerical ones. However, the measured center frequency is about 100 MHz higher than the designed one.

• Communications for Statistical Applications and Methods
• /
• 제27권4호
• /
• pp.469-486
• /
• 2020

Entropy is an important term in statistical mechanics that was originally defined in the second law of thermodynamics. In this paper, we consider the maximum likelihood estimation (MLE), maximum product spacings estimation (MPSE) and Bayesian estimation of the entropy of an inverse Weibull distribution (InW) under a generalized type I progressive hybrid censoring scheme (GePH). The MLE and MPSE of the entropy cannot be obtained in closed form; therefore, we propose using the Newton-Raphson algorithm to solve it. Further, the Bayesian estimators for the entropy of InW based on squared error loss function (SqL), precautionary loss function (PrL), general entropy loss function (GeL) and linex loss function (LiL) are derived. In addition, we derive the Lindley's approximate method (LiA) of the Bayesian estimates. Monte Carlo simulations are conducted to compare the results among MLE, MPSE, and Bayesian estimators. A real data set based on the GePH is also analyzed for illustrative purposes.

• Journal of the Korean Data Analysis Society
• /
• 제20권6호
• /
• pp.2747-2757
• /
• 2018

We consider the MLE (maximum likelihood estimate) and Bayesian estimates of three-parameter bathtub-shaped lifetime distribution based on the progressive type II censoring with binomial removal. Jung, Chung (2018) proposed the three-parameter bathtub-shaped distribution which is the extension of the two-parameter bathtub-shaped distribution given by Zhang (2004). Jung, Chung (2018) investigated its properties and estimations. The maximum likelihood estimates are computed using Newton-Raphson algorithm. Also, Bayesian estimates are obtained under the balanced loss function using MCMC (Markov chain Monte Carlo) method. In particular, BSEL (balanced squared error loss) function is considered as a special form of balanced loss function given by Zellner (1994). For comparing theirs MLEs with the corresponding Bayes estimates, some simulations are performed. It shows that Bayes estimates is better than MLEs in terms of risks. Finally, concluding remarks are mentioned.

• Journal of the Korean Statistical Society
• /
• 제22권1호
• /
• pp.55-69
• /
• 1993

Consider the problem of estimating an arbitrary continuous vector function under a weighted quadratic loss in the multiparameter exponential family with the density of the natural form. We first provide, using Blyth's (1951) method, a set of sufficient conditions for the admisibility of (possibly generalized Bayes) estimators and then treat some examples for normal, Poisson, and gamma distributions as applications of the main result.

• 한국안전학회지
• /
• 제34권4호
• /
• pp.95-102
• /
• 2019

The purpose of this study is to investigate the correlation between aluminum form work and noise-induced deafness by conducting special health examination on construction aluminum worker and noise measurement at the workplace. All the 11 aluminum form workers were diagnosed with noise-induced deafness after holding a special health examination. The workers have not had any previous history of noise-induced deafness which indicates that aluminum form work is related to noise-induced deafness disease. The impact noise of 120 dB(A)~125 dB(A), which exceeds the regulations of industrial safety and health act, was found during the dismantling rather than installation when noise measurement was made at the aluminum workplace. The aluminum form workers could permanently lose the hearing sense if they are exposed to this impact noise. This study is to suggest the method to prevent noise-induced deafness for aluminum form workers by firstly giving out hearing protection equipment at the construction site and secondly installing rubber mat, soundproof panel as well as changing the noise-lowering technique.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
• /
• pp.423-433
• /
• 2002

A very fast method of moments(MoM) for the analysis of microstrip structure is considered based upon the use of rooftop basis and razor test functions in conjunction with a new closed-form Green's functions. The present method presents a robust approach to obtain the Green's functions which can be derived by use of only one set of approximation parameters independently of operating frequency range. Moreover, using the present MoM scheme, the MoM matrix elements can be analytically evaluated with few number of terms in comparison with the previous method. So, the computational efficiency can be improved significantly without loss of the precision. In order to check the validity of the present method, performance is demonstrated for the example of a coaxially-fed microstrip transmission line and the present results are compared with the previous results.

• Journal of Power Electronics
• /
• 제12권6호
• /
• pp.960-973
• /
• 2012

The winding loss analysis of a flyback transformer is difficult and ambiguous because the primary side current and the secondary side current differs both in shape and phase, especially for DCM (Discontinuous Conduction Mode) operation. Meanwhile, the fringing field caused by the air gaps further makes the traditional 1-D loss analysis model not directly applicable. The paper gives a thorough investigation into the phase shift of winding currents, which indicates that the phase shift of the high order harmonics is still close to $180^{\circ}$ out-of-phase. Based on the analysis, a simplified 2-D winding loss analytical model for flyback transformers considering the effects of low order harmonics is proposed. By neglecting the y components of the fringing field, the proposed model has an acceptable accuracy and a simple form that is similar to the conventional 1-D model. The power loss calculated with the proposed analysis model is verified by FEA (Finite Element Analysis) simulations and experimental results.

• 한국정보과학회논문지:정보통신
• /
• 제29권2호
• /
• pp.181-187
• /
• 2002

Connection admission control(CAC), which decides whether or not to accept a new call request, is one of the most Important preventive congestion control techniques in asynchronous transfer mode(ATM) networks. To develop a practical CAC scheme, first we propose a "Modified Cell Loss Probability MP${\nu}"$, which is based on "Virtual Cell Loss Probability P${\nu}"$, taking into account mean burst duration of input traffic source and buffer size in ATM networks. MP${\nu}"$ computes more accurate cell loss probability than P${\nu}"$ without increasing computational complexity, since P${\nu}"$ is formulated simply form the maximum and the average cell rate of input traffic. P${\nu}"$ is overestimated as compared to the real cell loss probability when the mean burst duration is relatively small to the buffer capacity. Then, we Propose a CAC scheme, based on "Modified Virtual Bandwidth(MVB)" method, which may individualize the cell loss probabilities in heterogeneous traffic environments. For the proposed approach, we define the interference intensity to identify interferences between heterogeneous traffic sources and use it as well as MP${\nu}"$ to compute MVB. Our approach is well suitable for ATM networks since it provides high bandwidth utilization and guarantees simple and real time CAC computation for heterogeneous traffic environments.heterogeneous traffic environments.

• ETRI Journal
• /
• 제41권4호
• /
• pp.415-425
• /
• 2019

Generative adversarial networks (GAN) have been successfully used in many image restoration tasks, including image denoising, super-resolution, and compression artifact reduction. By fully exploiting its characteristics, state-of-the-art image restoration techniques can be used to generate images with photorealistic details. However, there are many applications that require faithful rather than visually appealing image reconstruction, such as medical imaging, surveillance, and video coding. We found that previous GAN-training methods that used a loss function in the form of a weighted sum of fidelity and adversarial loss fails to reduce fidelity loss. This results in non-negligible degradation of the objective image quality, including peak signal-to-noise ratio. Our approach is to alternate between fidelity and adversarial loss in a way that the minimization of adversarial loss does not deteriorate the fidelity. Experimental results on compression-artifact reduction and super-resolution tasks show that the proposed method can perform faithful and photorealistic image restoration.

• 대한수의학회지
• /
• 제40권3호
• /
• pp.587-599
• /
• 2000

This study was conducted to observe the severity of the disease and pathogenecity of Babesia gibsoni parasite on the splenectomized dogs(SPD) and nonsplenectomized(intact) dogs (NSPD) experimentally infected with B gibsoni. The average prepatent period was 4 days in the SPD and 8 days in the NSPD, respectively. Peak parasitaemia(PE) ranged from 26% to 34% of erythrocytes infected in the SPD and from 4% to 5% in the NSPD. Latent parasitaemia was still detectable 40 days as low as under 1.0% of erythrocytes infected after the initial parasitaemia in the SPD. Blood packed cell volume(PCV) decreased to as little as 6.4% to 6.9% in the SPD. The clinical signs were mild fever and anemia in the NSPD, remissions and exacervations of temperature, intermittent or spike-like increases of temperature, progressive polychromatophilic macrocytic anemia with anisocytosis, icterus, marked loss of appetite, rarely haemoglobinuria, and deep brown-yellowish urine in the SPD. Gross pathologic changes mainly involved slightly enlargement of liver and spleen in the NSPD and marked enlargement of liver in the SPD. Anatomic changes associated with the disease included diffuse periportal and centrilobular hephatitis, and membranoproliferative glomerulonephritis. Hyaline droplets, resulting protein metabolic alterations, were found in the convoluted ephithelium of the kidney. The density of lymphocytes within the liver sinusoids was markedly increased. Aggregates of large monocytes and macrophages were demonstrated in the centrilobular veins of the liver. The density of these cells in the centrilobular veins were greatest in the SPD. The forms of B gibsoni parasite found in the acute stage of SPD were large signet ring form, small signet ring form, pyriform, elongated form, comma form, head-phone form, oval form, peared form, racket-like form, amoeboid form, triangle form, quartered form, dot form, band form and multiple, and rosette form, et al. The severity of the disease and pathogenecity of B gibsoni parasite were mild in the NSPD but fatal in the SPD.