• Journal of the Korean Statistical Society
• /
• 제33권3호
• /
• pp.323-337
• /
• 2004

This article coined a general class of estimators for various measures in normal population when some' a priori' or guessed value of standard deviation a is available in addition to sample information. The class of estimators is primarily defined for a function of standard deviation. An unbiased estimator and the minimum mean squared error estimator are worked out and the suggested class of estimators is compared with these classical estimators. Numerical computations in terms of percent relative efficiency and absolute relative bias established the merits of the proposed class of estimators especially for small samples. Simulation study confirms the excellence of the proposed class of estimators. The beauty of this article lies in estimation of various measures like standard deviation, variance, Fisher information, precision of sample mean, process capability index $C_{p}$, fourth moment about mean, mean deviation about mean etc. as particular cases of the proposed class of estimators.

• The Korean Journal of Ecology
• /
• 제15권3호
• /
• pp.231-246
• /
• 1992

In order to estimate effects of air pollution for pinus thunbergii forests arounding onsan industrial complex, structure of forest vegrtation was surveyed. In the survey of forest vegetation, pinus densiflora have been died or being withered, and importance value(I.V) of rhododendron mucromulatum and lespedeza spp. were low at the vicinity of industrial complex. Especially lespedeza maximowiczii and l. maritima were not entirely appeared at the vicinity of industrial complex. I.V. of quercus serrata, robinia pseudoacacia and alnus firma were preferably high at the vicinity of industrial complex, and those of smilax china, rubus crataegifolius and rhus trichocarpa were similar at every site and it could be guessed that those had a tolerance. Number of species had a difference over 10 species at the vicinity of industrial complex as compared with those of remote sites, and species diversity showed highly at the farther sites of industrial complex, and also at the low layer, number of species, species diversity and evennes were low at the vicinity of industrialcomplex and species weakened to air pollution were disappearing. It was possible that forest vegetation would be changed from pinus spp. to community of a. firma and r. pseudoacacia.

• E2M - 전기 전자와 첨단 소재
• /
• 제8권6호
• /
• pp.708-714
• /
• 1995

We have discussed the buried-channel(BC) behavior through the subthreshold characteristics of submicron PMOSFET device fabricated with twin well CMOS process. In this paper, we have guessed the initial conditions of ion implantation using process simulation, obtained the subthreshold characteristics as a function of process parameter variation such as threshold adjusting ion implant dose($D_c$), channel length(L), gate oxide thickness($T_ox$) and junction depth of source/drain($X_j$) using device simulation. The buried channel behavior with these process prarameter variation were showed apparent difference. Also, the fabricated pMOSFET device having different channel length represented good S.S value and low leakage current with increasing drain voltage.

• 한국세라믹학회지
• /
• 제29권5호
• /
• pp.410-418
• /
• 1992

Si3N4, AlN and Y2O3 powder mixtures of the Y0.1(Si, Al)12(N, O)16 composition were hot-pressed at 1900℃ for 0 to 60 min under 30 MPa in order to fabricate the partially-stabilized α-Sialon ceramics (X=0.1). Room and high temperature flexural strengths of the specimens were compared with those of Si3N4-5 wt%Y2O3, Si3N4-5 wt%Y2O3-2 wt%Al2O3, and β-Sialon (Z=0.5) ceramics. The flexural strength of the α-Sialon ceramics which was hot-pressed for 15 min showed the highest value of 820 MPa at 1400℃ that is relatively higher temperature. It is guessed that a little amount of glassy phase existed in grain boundary because Y2O3 and AlN components were incoperated in Si3N4 grains, or transient liquid phase sintering, and microstructure with the smaller grain size and the interlocked grains of α'-and β-Si3N4 was obtained by the hot-pressing at high temperature of 1900℃ for the short time (15 min).

• 한국정밀공학회지
• /
• 제28권6호
• /
• pp.670-677
• /
• 2011

This study is to estimate the joint torques without torque sensor using the EMG (Electromyogram) signal of agonist/antagonist muscle with Neural Network Back Propagation Algorithm during the elbow motion. Command Signal can be guessed by EMG signal. But it cannot calculate the joint torque. There are many kinds of field utilizing Back Propagation Learning Method. It is generally used as a virtual sensor estimated physical information in the system functioning through the sensor. In this study applied the algorithm to obtain the virtual senor values estimated joint torque. During various elbow movement (Biceps isometric contraction, Biceps/Triceps Concentric Contraction (isotonic), Biceps/Triceps Concentric Contraction/Eccentric Contraction (isokinetic)), exact joint torque was measured by KINCOM equipment. It is input to the (BP)algorithm with EMG signal simultaneously and have trained in a variety of situations. As a result, Only using the EMG sensor, this study distinguished a variety of elbow motion and verified a virtual torque value which is approximately(about 90%) the same as joint torque measured by KINCOM equipment.

• 한국지반공학회논문집
• /
• 제20권2호
• /
• pp.125-130
• /
• 2004

본 논문에서는 수치적 구성방정식인 연속 탄소성 캡 모델의 정수추정에 관한 방법이 제시되었다. 캡 모델을 이용하여 실제 토질의 거동을 예측하기 위하여서는 캡 모델을 이루는 토질의 물성과 직접적으로 연관된 여덟개의 정수가 결정되어야 한다. 이를 위하여 첫 번째로, Ottawa 모래를 사용하여 표준압밀시험기를 이용한 일축압축시험 및 배수삼축압측 시험이 토질거동의 실제기준값으로서 수행되었고, 두 번째로 탄소성 캡 수치해석모델의 반응을 실내실험값에 일치시키기 위하여 추정된 정수들을 사용한 수치실험이 수행되었다. 두 실험 간의 오차를 최소화하기 위하여 최적화 기법이 사용되었으며, 최적화 후 결정된 8개의 정수는 실내실험결과와 비교되었다. 특히, 수치적 삼축압축시험시 응력계산에 따른 수평변위 측정에 특별한 주의가 필요하다.

• The Korean Journal of Ceramics
• /
• 제5권2호
• /
• pp.165-170
• /
• 1999

The strain sensing properties of th system xNiO-(1-x) CaO with various compositions (x=0.001-0.05) are evaluated and the origin of the phenomena is guessed. We have found out that the high temperature electrical conductivity of the xNiO-(1-x)CaO increases by applying the compressive stress at $1000^{\circ}C$. When the applied load is removed, the electrical conductivity rapidly decreases and returns to the original value, but a small hysteresis of the stress-conductivity curve is observed. After the loading test, the lattice parameter of the specimen is found lengthened. The correlation between the lengthening of the lattice parameter and the increases in the electrical conductivity by loading is discussed. The amount of the "expanded type" Ni(II)O6 clusters in the xNiO-(1-x)CaO grains is supposed to be increased by the applied stress, which would be the origin of the strain dependent electric conduction in the xNiO-(1-x)CaO system.aO system.

• 한국조경학회지
• /
• 제46권1호
• /
• pp.106-114
• /
• 2018

본 연구는 조경분야 종사자들을 대상으로 직무환경이 직무만족에 미치는 영향을 파악하기 위하여 설문조사를 통한 실증분석을 하였다. 직무환경요인이 직무만족에 미치는 영향을 다중회귀분석한 결과, 직무만족에 근무여건(p<0.01), 대인관계(p<0.00), 보상체계(p<0.05)는 정(+)의 영향을 미치고, 업무량(p<0.05)은 통계학적으로 유의하지 않은 것으로 나타났다. 직무환경요인 중에서 계수 값이 가장 높은 것은 대인관계로 ${\beta}$값이 0.233이었다. 업무량이 직무만족에 미치는 영향에 대하여 유의성 여부는 기존의 여러 연구에서도 엇갈리고 있는데, 이것은 '직무인식 상황에 따라 업무를 수동적으로 인식하든가 또는 능동적으로 인식하든가'에 따라 다를 것으로 생각되었다. 조경종사자들의 업무량이 직무만족에 통계학적으로 유의하지 않는 것은 조경종사자들의 경우에는 자신들이 하고 있는 일이 적성에 맞고, 의미 있는 일이라고 생각하며, 사회적으로 기여하는 바가 있다고 인식되면 어렵고 많은 업무량도 기꺼이 자기의 역량이 커짐을 보람으로 삼고, 자기발전과 자기실현의 성취감이 크기 때문일 것으로 추정되었다.

• 대한본초학회지
• /
• 제24권3호
• /
• pp.13-19
• /
• 2009

Objectives : This study was aimed to define the protective effect of Tissue Cultured Root of Wild Ginseng (CWG) against doxorubicin (Doxo) toxicity, and investigate the anti-tumor synergic effect of CWG in combination with Doxo in tumor-bearing C57BL/6 mice. Methods : Tumor-bearing mice were established by single inoculation with B16/F10 melanoma cells (2$\times$10$^6$/ml) subcutaneously. Tumor-bearing mice (tumor volume between 50-100 mm$^3$) were selected and divided them into control, Doxo, and Doxo+CWG group. Mice of Doxo group were received with Doxo (4 mg/kg of B.W.) intraperitoneally at 0, 4, 8 days after starting the experiment. Mice of Doxo+CWG group were received CWG water extract during 12 days in combination with Doxo treatment. The body weight, tumor volume, tumor weight, and organ weight (heart, liver, kidney, and testis) were measured. And serum SPK, GOT and creatinine values were analysed. Results : The volume and weights of tumor masses in Doxo group were decreased significantly compared with the those of control group. And the those of Doxo+CWG group were not significantly different from the those of Doxo group. Whereas the weight of body, liver, kidney and testis in Doxo+CWG group were increased significantly compared with the those of Doxo group. The level of serum CPK and GOT in Doxo group were increased compared with the those of control group. But the value of Doxo+CWG group were decreased significantly compared with the values of Doxo group. Conclusions : These results suggest that CWG has protective effect against doxorubicin toxicity. And these effect is guessed that is caused in augmentation of vital energy.

• Clinical and Experimental Reproductive Medicine
• /
• 제25권3호
• /
• pp.251-260
• /
• 1998

It is well known that the clinical test for responsibility of accurate fertilization capacity in male partners is very important to diagnose and treat the infertility. However, it has been reported that the traditional semen analysis cannot accurately predict fertilization and pregnancy potential. The present study was performed to evaluate the acrosomal reaction to ionophore challenge (ARIC) test as a prognostic indicator for fertilization of sperm and oocyte in an in vitro fertilization and embryo transfer (IVF-ET) program. From March 1996 to Februry 1997, 30 couples undergoing IVF program were allocated to this study group. All female partners in the study group were 35 years old or less and their serum level of basal follicle stimulating hormone (FSH) and estradiol $(E_2)$ were normal. All the male partners have normal parameters of semen analysis. The ARIC tests were performed on the day of ovum pick up and in vitro insemination in all the male partners. The controlled ovarian hyperstimulation (COH) using luteal long protocol of gonadotropin releasing hormone (GnRH) agonist was used in all couples for IVF-ET. The acrosomal reaction with $10{\mu}l$ of 10% DMSO was induced spontaneously in $10.1{\pm}9.8%$, and acrosomal reaction with calcium ionophore A 23187 was induced in $27.4{\pm}18.1%$, and the ARIC value was $17.4{\pm}16.2%$. There were no significant correlation between the ARIC value and the fertilization rate ($r^2$=0.044, p=0.268). There were also no significant correlation between the ARIC value and the percentage of the grade I, II embryos ($r^2$=0.046, p=0.261). On the basis of above results, it was suggested that ARIC test might not be a useful prognostic indicator for fertilization in IVF-ET in male partners with normal parameters of conventional semen analysis. We guessed that IVF-ET could be performed to the patients primarily without universal appilcation of ARIC test to all male partenrs, and if fertilization failure occurs, the micro assisted fertilization (MAF) such as intracytoplsmic sperm injection (ICSI) might be used as an alternative mode of treatment with acceptable success rate.