• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.307-312
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• 2000

Asynchronous transfer mode(ATM) is flexible to support the various multimedia communication services such as data, voice, and image by applying asynchronous time-sharing and statistical multiplexing techniques to the existing data communication. ATM service is categorized to CBR, VBR, UBR, and ABR according to characteristics of the traffic and a required service qualities. Among them, ABR service guarantees a minimal bandwidth and can transmit cells at a maximum transmission rate within the available bandwidth. To minimize the cell losses in transmission and switching, a feedback information in ATM network is used to control the traffic. In this paper, predictive control algorithms are proposed for the feedback information. When the feedback information takes a long propagation delay to the backward nodes, ATM switch can experience a congestion situation from the queue length increases, and a high queue length fluctuations in time. The control algorithms proposed in this paper provides predictive control model using slop changes of the queue length function and previous data of the queue lengths. Simulation shows the effectiveness result of the proposed control algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.685-690
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• 2021

In this paper, we propose a deep learning-based transmit power control scheme to maximize the sum-rates while satisfying the minimum data-rate in downlink non-orthogonal multiple access (NOMA) systems. In downlink NOMA, we consider the co-channel interference that occurs from a base station other than the cell where the user is located, and the user feeds back the signal-to-interference plus noise power ratio (SINR) information instead of channel state information to reduce system feedback overhead. Therefore, the base station controls transmit power using only SINR information. The use of implicit SINR information has the advantage of decreasing the information dimension, but has disadvantage of reducing the data-rate. In this paper, we resolve this problem with deep learning-based training methods and show that the performance of training can be improved if the dimension of deep learning inputs is effectively reduced. Through simulation, we verify that the proposed deep learning-based power control scheme improves the sum-rate while satisfying the minimum data-rate.

• The Korean Journal of Franchise Management
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• v.7 no.1
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• pp.13-20
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• 2016

Purpose - In the past, the chain hotel chefs only serve food to their customers. However recently, the hotel chefs play a pivotal role in hotel including considering various customer preferences, safety and nutrition of food, and increasing profits through effective human resource management and inventory control. With the change of the chain hotel chef's' roles, pygmalion leadership, one of new leadership styles, focuses on the effect that leader's positive expectation let subordinates have motivation and more engage in work. This study investigates the effect of chain hotel chef's pygmalion leadership on leader trust and organizational trust. Research design, data, and methodology - This study was to investigate the structural relationships among chain hotel restaurant chefs' pygmalion leadership, hotel restaurant cooks' leader trust, organizational trust, and teamwork, and how leader trust and organizational trust play mediating roles in the relationship between pygmalion leadership and teamwork. In this model, pygmalion leadership includes 4 dimensions: Climate, Feedback, Input, and Output. Data were collected using self-administered questionnaire survey on cooks of Deluxe hotel restaurants located in Seoul and Gyonggi-Do. The samples for data analyses were 243 excepting unusable responses. Result - The findings can be summarized as follows: First, climate and feedback had a positive effect on leader trust, respectively. Second, feedback and output had a statistically positive effect on organizational trust, respectively. Third, leader trust had positive effects on organizational trust and teamwork. Fourth, organizational trust had a significant effect on teamwork. Conclusions - As a chain hotel chef treats his/her staffs sincerely, they will be more engaged in work by establishing trust in their leader. Ultimately, it leads to higher sales profit and customer satisfaction. In addition, a hotel can encourage chefs and other staffs to treat each other as if the student-instructor relations, not just commanding staffs. Then, cooks build up their trust to their leader and organization for its sustained growth and development, and the internal bond in organization including teamwork is strengthened. Therefore, to strengthen teamwork and organizational trust, there should be active communication, knowledge sharing, goal sharing, and cooperation between chefs and cooks.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.109-122
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• 2023

As platforms become primary decision making tools, platforms for decision have been introduced to improve quality of decision results. Because, decision platforms applied augmented decision-making process which uses experiences and feedback of users. This process creates a variety of alternatives tailored for users' abilities and characteristics. However, platform users choose alternatives before considering significant quality factors based on securing decision quality. In real world, platform managers use an algorithm that distorts appropriate alternatives for their commercial benefits. For improving quality of decision-making, preceding researches approach trying to increase rational decision -making ability based on experiences and feedback. In order to overcome bounded rationality, users interact with the machine to approach the optional situation. Differentiated from previous studies, our study focused more on characteristics of users while they use decision platforms. This study investigated the impact of quality factors on decision-making using platforms, the dimensions of systematic factors and user characteristics. Systematic factors such as platform reliability, data quality, and user characteristics such as user abilities and biases were selected, and measuring variables which trust, satisfaction, and loyalty of decision platforms were selected. Based on these quality factors, a structural equation research model was created. A survey was conducted with 391 participants using a 7-point Likert scale. The hypothesis that quality factors affect trust was proved to be valid through path analysis of the structural equation model. The key findings indicate that platform reliability, data quality, user abilities, and biases affect the trust, satisfaction and loyalty. Among the quality factors, group bias of users affects significantly trust of decision platforms. We suggest that quality factors of decision platform consist of experience-based and feedback-based decision-making with the platform's network effect. Through this study, the theories of decision-making are empirically tested and the academic scope of platform-based decision-making has been further developed.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.519-524
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• 2023

The study summarizes the experience of operation in the application of flipped learning to various IT-related liberal arts subjects, and proposes a specific application method. So far, most of the studies have analyzed various strategies and learner responses to flipped learning. Currently, it is the time when teachers, who are the main operators of the flipped learning class, need to study how to provide immediate feedback and application while running the relevant courses. Studies related to this are gradually coming out. In general, most of the studies on sharing reference materials through the results after applying various strategies such as developing the structure of class operation by instructors themselves, combining them with discussion classes, or developing various contents. This study proposes a method to analyze how various strategies can be applied in the subject and obtain results simultaneously with class operation by analyzing unstructured data, which is a survey that can receive immediate feedback.

• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.249-255
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• 2017

The domestic tourism industry mostly relies on quantitative surveys for customer satisfaction. However, customer participation of the questionnaires is extremely low and the improvement of the dissatisfactory factors is not being performed promptly. In this paper, we propose a new topic map system and prove its empirical effectiveness to improve the accuracy of customer feedback information and the efficiency of the analysis process. The topic map system is a system for analyzing large amounts of customer feedback data in real time. It uses text mining and ontology techniques by integrating data collected over a certain period from real-time SNS and quantitative data obtained from existing survey systems. The effect after improving the analyzed factors of dissatisfaction is also a new and innovative evaluation system for monitoring customer satisfaction in real time. The classification based on this integrated data is a classification system that is specific to the product or the customer. According to this classification, it is possible to measure the effect of the recognition and improvement of the complaint factor in real time on the topic map system. This provides a sophisticated prioritization of the improvement factors and enables customer satisfaction quality control as a PDCA feedback system. In addition, the survey period and costs are greatly shortened, and responses can be more precise to the existing survey method. As a practical application, this system is applied to the largest H travel agency in Korea to prove the accuracy and efficiency of the proposed system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2081-2093
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• 1994

In this study, we design and implement 64 QAM demodulator which has 155 Mbps, first level of CCITT G707 SDH(Synchronous Digital Hierachy) for STM 1 signal transmission. Carrier recovery which effects the demodulator performance uses decision feedback carrier using 8 bits A/D converter. Also, PSF(Pulse Shaping Filter) is 7 order elliptic filter. Carrier recovery circuit is designed and implemented digital type which use high 3 bits of 8 bits conversion data as data and the order low bits as error data and hybrid type which use VCO and analog integrator. Therefore we obtain stable performance recovery.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.104-110
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• 2006

The advantage of the DSM which employ multi-bit quantizer is the increased SNR at the modulator's output. Typically 6 dB improvement is effected for every one additional bit. But multi-bit quantizer evidently requires multi-bit DAC in the feedback loop. The integral linearity error of the feedback DAC has direct impact upon the system performance and degraded SNR of the system. In order to mitigate the negative impact the DAC has on the system performance, many DEM(Dynamic Element Matching) schemes has been proposed. Among the proposed schemes, four schemes(DER,CLA,ILA,DWA) are explained and its performance has been compared. DWA(Data Weighted Averaging) method shows the best performance of the all.

• Journal of Welding and Joining
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• v.19 no.4
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• pp.384-390
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• 2001

There have been many problems due to deformation in industry field. Especially, it is severe in parts with small size and thin thickness and in products that must have excellent airtightness and anti-noise. The countermeasures for this deformation in field have mainly been dependent on the rule of trial and error by operator's experience because of productivities. Systematic study about this product with deformation is also insufficient that deformation is complex problem with shape, size, material of product, joining method and conditions, etc.. It is efficient to apply CAE technique without influence on productivity to this problem. There is, however much difference between the result analyzed by CAE and appearances in working field because of the insufficiency of communication between simulator and worker and of sensing data for boundary condition in analysis. In this study, to solve this deformation problem, we intend to make a simulation model that is adapted from working conditions by tuning and feedback between sensing data and simulation results. This paper include temperature monitoring and make a heat transfer model using sensing data in product as previous step for deformation analysis. The heat transfer analysis of shrinkage fit process is considerably difficult due to contact heat transfer between case and core. To solve this contact problem, gap element is used in present study.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.719-720
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• 2006

In the mechanical system, optimization of motion control is very essential in the aspect of automation technique progress. In the servo system, the function of controller is very important but most of the controllers have played only the role of pulse generator because the controller with main function is very expensive. In this thesis, the system was composed of PC, commonly used driver AC servo motor and a produced control board. The PC transmit a gain, a locus data to a driver and controller. At the same time, it converts imformation from the controller and convert them into data and offer an output with graph. The role of a controller is to trasmit a locus data to a driver and counting the pulse on the phase of an encoder to the PC. We have performed the experiment in order to confirm with variable PID parameter capable of the optimization of gain tuning with the counting of feedback control sensor signal with regard to the external interface into the system, such as torque. Based on the experiment result, we have confirmed as follows: First, it was confirmed that we could easily input control factors P.I Gain, constant $K_P,\;K_I$ into PC. Second, not only pulse generator function was possible, but with this pulse it was also possible to count using software with PIC chip. And third, using the multi-purpose PIC micro chip, simple operation and the formation of small size AC Servo Controller was possible.