• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1805-1810
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• 1991

This paper derives the upper and the lower bound of the mean cycle time and the mean service time of the class 6 and the class 4, within which the minimum utilization constrain of the class 4 is guaranteed. Also, derived are conditions under which the token bus network is stable or unstable. These bounds and stable conditions are represented in terms of the high priority token hold time, the token rotation time and the arrival rate and the total station number etc. This paper suggest a parameter tuning algorithm in a partially symmetric token bus network with two classes, which maximizes the token rotation time for a suitable high priority token hold time and at the same time meets the stability condition of the network, the real time constraint and the minimum utilization constraint of the class 4.

• Management Science and Financial Engineering
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• v.14 no.1
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• pp.35-63
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• 2008

We discuss the problem of selecting profitable customer orders arriving at a company providing two classes of services. For an arriving customer order for the first class, the company 1) makes a decision whether to accept or reject it (admission control), or 2) decides a price of the order to offer to an arriving customer (pricing control). The customer order undergoing processing in the system may be cancelled owing to unavoidable circumstances with the customer. The second class of service is provided as a sideline, which prevents the server from being idle when all the customer orders for the first class are completed and delivered. This yields the sideline profit. We discuss both admission control and pricing control problems in an identical framework as well as examine the structure of the optimal policies maximizing the total expected present discounted net profit gained over an infinite planning horizon.

• Journal of the Korean Data and Information Science Society
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• v.1
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• pp.7-33
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• 1990

Bechhofer and Tamhane(1981) developed a theory of optimal incomplete block designs for comparing several treatments with a control. This class of designs is appropriate for comparing simultaneously $p{\geq}2$ test treatments with a control treatment (the so-called multiple comparisons with a control (MCC) problem) when the observations are taken in incomplete blocks of common size $K{\<}p+1$. In this paper we want to extend to partially BTIB designs with two associate classes for the MCC problem. We propose a new class of incomplete block designs that are partially balanced with respect to test treatments. Because the class of designs that we consider is larger than the class of designs in Bechhofer and Tamhane and provides us with designs that improve on the optimal designs in their class. We shall use the abbreviation PBTIB to refer to such designs. We study their structure and give some methods of construction. Also we describe a procedure for making exact joint confidence statements for the MCC problem in PBTIB Designs with two associate classes. We study Optimality, Admissibility considerations in PBTIB designs with two associate classes.

• The korean journal of orthodontics
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• v.20 no.2
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• pp.333-354
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• 1990

This study was designed to analyse vertical dysplasia such as open bite or deep bite in persons with skeletal Class III malocclusion. The subjects consisted of 60 control patients, 40 Class III open bite patients and 40 Class III deep bite patients. The mean age was 19.8 years in the control group, 17.8 years in the Class III open bite group and 16.5 years in the Class III deep bite group. The results were as follows: 1. In Class III malocclusion patients, the characteristics of the vertical dysplasia are under the palatal plane. 2. In Class III malocclusion patients, the items showing the characteristics of the vertical dysplasia are mandibular plane angle, lower gonial angle, lower facial height, dental height & inclination of the upper first molar, interincisal angle, maxillary & mandibular occlusal plane angle. 3. In Class III malocclusion patients, LPFH/LAFH ratio shows the highest significance among the facial height ratios. 4. In Class III malocclusion patients, open bite group has a upward cant of maxillary occlusal plane & downward cant of mandibular occlusal plane. And deep bite group has a downward cant of maxillary occlusal plane & upward cant of mandibular occlusal plane. 5. In Class III malocclusion patients, the molar teeth of the open bite group are measially inclined and those of the deep bite group are upright.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1678-1688
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• 2016

This paper presents a capacitive power transfer (CPT) system using a Class-E resonant inverter. A Class-E resonant inverter is chosen because of its ability to perform DC-to-AC inversion efficiently while significantly reducing switching losses. The proposed CPT system consists of an efficient Class-E resonant inverter and capacitive coupling formed by two flat rectangular transmitter and receiver plates. To understand CPT behavior, we study the effects of various coupling distances on output power performance. The proposed design is verified through lab experiments with a nominal operating frequency of 1 MHz and 0.25 mm coupling gap. An efficiency of 96.3% is achieved. A simple frequency tracking unit is also proposed to tune the operating frequency in response to changes in the coupling gap. With this resonant frequency tracking unit, the efficiency of the proposed CPT system can be maintained within 96.3%-91% for the coupling gap range of 0.25-2 mm.

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.209-216
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• 2014

The purpose of this study was to explore the effect of 8 weeks after school classes of track sports on students' start motion through kinematic variables. 30 students in D National university of education participated for this study. These students divided into two groups, 17 students for experimental group and 13 students for control group. The two groups participated in general athletic class as common class, and the experimental group participated in after school class additionally. The general class taught track and jump skill for 3 hours a week, and the after school class taught only athletic running skill for 30 minutes a week. Pre and post test assessed to assess students' kinematic changes. Findings indicated that velocity and step rate were increased, and contact time, step length, displacement of center of mass were decreased in the experimental group. In the control group, early velocity, knee/hip angle velocity were increased, and contact time, step length, displacement of center of mass were decreased. In conclusion, the students who only participated in general class, could not maintain athletic skills obtained from the class. However, students who participated in both general and after school class accomplish athletic start skill. This is because Continuous learning effect helped students keep the skill and did not lose the skill. Thus, in order for students to learn specific sport skills, joining after school class with general class together is recommended.

• The korean journal of orthodontics
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• v.44 no.1
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• pp.13-19
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• 2014

Objective: The aim of this study was to evaluate long-term changes in the pharyngeal airway dimensions after functional appliance treatment in adolescents with skeletal Class II malocclusions. Methods: Pharyngeal airway dimensions were compared between subjects with skeletal Class II malocclusions (n = 24; mean age: $11.6{\pm}1.29$ years) treated with a Class II bionator and age-matched control subjects with skeletal Class I occlusions (n = 24; mean age: $11.0{\pm}1.21$ years) using a series of lateral cephalograms obtained at the initial visit (T0), after treatment (T1), and at the completion of growth (T2). Results: The length of the nasopharyngeal region was similar between adolescents with skeletal Class I and Class II malocclusions at all time points, while the lengths of the upper and lower oropharyngeal regions and the pharyngeal airway areas were significantly smaller in the skeletal Class II adolescents before treatment when compared to the control adolescents (p < 0.05). However, following treatment with a functional appliance, the skeletal Class II adolescents had increased pharyngeal airway dimensions, which became similar to those of the control subjects. Conclusions: Functional appliance therapy can increase the pharyngeal airway dimensions in growing adolescents with skeletal Class II malocclusions, and this effect is maintained until the completion of growth.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.2
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• pp.145-154
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• 2023

In this study, to control the heading angle of a ship, which is constantly subjected to various internal and external disturbances during the voyage, an LADRC (linear active disturbance rejection control) design that focuses more on improving the disturbance removal performance was proposed. The speed rate of change of the ship's heading angle due to the turn of the rudder angle was selected as a significant factor, and the nonlinear model of the ship's maneuvering equation, including the steering gear, was treated as a total disturbance. It is the similar process with an LADRC design for the first-order transfer function model. At this time, the gains of the controller included in LADRC and the gains of the extended state observer were tuned to RCGAs (real-coded genetic algorithms) to minimize the integral time-weighted absolute error as an evaluation function. The simulation was performed by applying the proposed GA-LADRC controller to the heading angle control of the Mariner class vessel. In particular, it was confirmed that the proposed controller satisfactorily maintains and follows the set course even when the disturbances such as nonlinearity, modelling error, uncertainty and noise of the measurement sensor are considered.

• Journal of Power Electronics
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• v.5 no.4
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• pp.272-281
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• 2005

In this paper, a simple power control scheme for a constant frequency Class-D inverter with a variable duty cycle is proposed. It is more suitable and acceptable for high- frequency induction heating (IH) jar applications. The proposed control scheme has the advantages of not only wide power regulation range but also ease of control output power. Also it can achieve a stable and efficient Zero-Voltage-Switching (ZVS) in a whole load range. The control principles of the proposed method are described in detail and its validity is verified through simulated and experimental results on 42.8kHz IGBT for induction heating rated on 1.6kW with constant frequency variable power.

• Hwankyungkyoyuk
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• v.20 no.4
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• pp.166-179
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• 2007

The purpose of this study is to find a concrete plan by examining effect of environmental education program on Environment-friendly Attitudes in sixth grade elementary school and to testify the educational values of environmental education program. The study was carried out by 32 students, which was experimental group and by 32 students, control group, in the sixth grade of Y elementary school located in yangjung, Busan city. Both group was found out the same quality group through the pre-test. Environmental class using environmental education program was applied to experimental group and traditional lecture class was applied to control group. After executing post-test to each group, comparative analysis was conducted by t-test using a SPSS 12.0 program. The result of post-test showed that experimental group taken environmental class using environmental education program was more statistically meaningful than control group taken traditional lecture class in the cognitive, emotional, behavioral area. As a result, in sixth grade elementary school environmental class using a environmental education program was more effective in knowledge-acquirement about the overall environ mental programs, and in fostering Environment-friendly Attitudes and behaviors than traditional lecture class. The teacher must develop efficient environment education program in such side.