• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.6
• /
• pp.41-50
• /
• 1995

A state-of-the-arts GaAs power metal semiconductor field effect transistor (MESFET) for 3.3V operation digital hand-held phone at 900 MHz has been developed for the first time, The FET was fabricated using a low-high doped structures grown by molecular beam epitaxy (MBE). The fabricated MESFETs with a gate width of 16 mm and a gate length of 0.8 .mu.m shows a saturated drain current (Idss) of 4.2A and a transconductance (Gm) of around 1700mS at a gate bias of -2.1V, corresponding to 10% Idss. The gate-to-drain breakdown voltage is measured to be 28 V. The rf characteristics of the MESFET tested at a drain bias of 3.3 V and a frequencyof 900 MHz are the output power of 32.3 dBm, the power added efficiency of 68%, and the third-ordr intercept point of 49.5 dBm. The power MESFET developed in this work is expected to be useful as a power amplifying device for digital hand-held phone because the high linear gain can deliver a high power added efficiency in the linear operation region of output power and the high third-order intercept point can reduce the third-order inter modulation.

• Journal of Korean Society for Quality Management
• /
• v.23 no.4
• /
• pp.1-12
• /
• 1995

Sample skewness has not received much attention from researchers to design a control chart. In this paper, control charts based on two skewness measures are studied to control a manufacturing process. One skewness measure is the third central moment about mean, the other is the third L-moment which is a linear combination of order statistics. Since the exact sampling distributions of two skewness measures are unknown, empirical sampling distributions are studied using simulation. The sampling distributions are used to design control charts for skewness and performance of two skewness measures is compared.

• Journal of Astronomy and Space Sciences
• /
• v.31 no.3
• /
• pp.199-204
• /
• 2014

This paper intends to highlight the effect of the third-body in an inclined orbit on a spacecraft orbiting the primary mass. To achieve this goal, a new origin of coordinate is introduced in the primary and the X-axis toward the node of the spacecraft. The disturbing function is expanded up to the second order using Legendre polynomials. A double-averaged analytical model is exploited to produce the evolutions of mean orbital elements as smooth curves.

• Communications of the Korean Mathematical Society
• /
• v.33 no.2
• /
• pp.437-444
• /
• 2018

Let S denote the class of analytic and univalent functions in the open unit disk $D=\{z:{\mid}z{\mid}<1\}$ with the normalization conditions f(0) = 0 and f'(0) = 1. In the present article, an upper bound for third order Hankel determinant $H_3(1)$ is obtained for a certain subclass of univalent functions generated by Ruscheweyh derivative operator.

• Journal of Contemporary Eastern Asia
• /
• v.16 no.2
• /
• pp.82-92
• /
• 2017

The Korean state evolved as a distinct entity in a region of major power convergence and conflict. All states, as human constructions, seek sovereignty and life security of their subjects/citizens, and are rotted in organic society. In the Republic of Korea, constitutional order has provided a framework for political action and a succession of regimes - authoritarianism, military dictatorship, and constitutional democracy. Since 1960 two paradigms have undergone a cycle of growth and decline, and a third, since the 2016 candlelight demonstrations in Gwanghwamun, may be the beginnning of a third generation paradigm - populist constitutionalism.

• Honam Mathematical Journal
• /
• v.45 no.2
• /
• pp.359-379
• /
• 2023

In the present paper, we study translation hypersurfaces in E⁴. In this context, firstly we obtain first, second and third Laplace-Beltrami (LB^I, LB^II and LB^III) operators of the translation hypersurfaces in E⁴. By solving second and third order nonlinear ordinary differential equations, we prove theorems that contain LB^I-minimal, LB^II-minimal and LB^III-minimal translation hypersurfaces in E⁴.

• The korean journal of orthodontics
• /
• v.30 no.4 s.81
• /
• pp.467-473
• /
• 2000

As a rectangular wire Is inserted into edgewise brackets the wire exerts a force system three-dimensionally. The force system may include bending force in first and second orders and a torsional force in third order Analytical and experimental studies on bending force have been Introduced, but information about torsion is still lack. The purpose of this study was to estimate the torsional moment in the force system of rectangular arch wires through theoretical and experimental studies. Wires most frequently used for third order control were selected as study materials. Cross sections of 0.016x0.022, 0.017x0.025, 0.019x0.025 inch rectangular wires in foot different materials such as stainless steel(Ormco), TMA(Ormco), NiTi(Ormco), and braided stainless steel (DentaFlex, Dentaurum) were used. The torque/twist rate of each test material was calculated using the torsion formula. Torque/twist rate, yield torsional moment, and ultimate torsional moment were measured with a torque gauge. The torsion formula assesses that the torque/twist rate (T/$\theta$) is proportional to the characteristics of material (G) and cross section (J), and is inversely proportional to the length of wire (L). Most experimental results corresponded with the formula. The relative stiffness was calculated for reference to a logical sequence of wire changes.

• Journal of Fisheries and Marine Sciences Education
• /
• v.25 no.5
• /
• pp.1214-1223
• /
• 2013

The purpose of this work is to analyze the factors, criteria and importance that shippers in the international logistics industry take into account in choosing third-party logistics, and thereby to propose the directions of the areas and functions that third-party logistics will need to enhance on the basis of Analytic Hierarchy Process (AHP) methodology. To do that, this work collected and analyzed materials about changing environments of logistic industry and previous studies, and especially conducted a questionnaire survey on the factors to choose third-party logistics with the study subjects of shippers in the international logistics industry. To draw attribute factors, this work repeatedly chose and classified candidate factors through Delphi technique on the basis of the data of previous studies. The analysis results are presented as follows: regarding pairwise comparison between logistic cost and logistic service in relation of conflict, logistic service was recognized to be more important than logistic cost; regarding pairwise comparison between corporate capability and logistic cost, logistic cost was recognized to be more important; and regarding comprehensive evaluation, logistic service factors, including accuracy of order handling, service reliability, freight damage and compensation, a degree of fulfillment of promise, quality of transportation, and problem-solving ability, were found to be in high position.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2006.10a
• /
• pp.240-257
• /
• 2006

In an effort to gain competitiveness, recently many companies are trying to outsource their logistics activities to the logistics specialists, while concentrating on their core and strategic business area. Because of this trend, the third party logistics comes to the fore, catching people's attention, and expanding its market rapidly. Under these circumstances, the third party logistics companies are making every effort to improve their logistics services and to develop an information system in order to enhance their competitiveness. In particular, among these efforts one of the critical parts is the decision support system for effective transportation network planning. To this end, this study has developed an efficient decision support system for an optimal transportation network planning by comprehensively considering the transportation mode, routing, assignment, and schedule. As a result of this study, the new system enables the expansion of the third party logistics companies' services including the multimodal transportation, not to mention one mode of transportation, and also gets them ready to plan an international transportation network.

• Journal of the Korean Institute of Gas
• /
• v.4 no.1 s.9
• /
• pp.1-8
• /
• 2000

Third party damage is one of the causes intrimiting the safety of a buried pipelines and it is very important to detect third party damage on pipelines as soon as possible. The purpose of this study is whether third-party damage can be detected by accelerometer sensor and how far the third-party damage signal can propagate. And a pilot experiment was carried out in order to find third-party damage location. As a result, the detected signal's spectum is high frequency at short distances, as the distance is far, the signals in high frequency range are attenuated and those in low frequency range remain. It was also proved that third-party damage within 5.3km distance can be detected by monitoring vibration signals.