• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.613-616
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• 2003

This paper describes the design and implementation of wideband 360$^{\circ}$ phase shifter by using I/Q vector method. One of four quadrants was selected by a switching operation and the desired phase value was obtained by varying attenuation level of attenuator located in I/Q path. The minimum phase RMS error of 3.6$^{\circ}$ and the maximum phase RMS error of 25.2$^{\circ}$ were measured over 6~180Hz frequency range. Those characteristics are good enough for the requirement of ECM radar equipment. The phase values can be adjusted by control module.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1773-1780
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• 2016

This paper proposes a wide air-gap control method for the multi-module permanent magnet linear synchronous motor (MM-PMLSM) based on independent vector control. In particular, the MM-PMLSM consists of symmetrical multi-module and multi-phase structures, which are basically three-phase configurations without a neutral point, unlike conventional three-phase machines. In addition, there are no additional magnetic levitation windings to control the normal force of the air-gap between each stator and mover. Hence, in this paper, a dq-axis current control applying a d-q transformation and an independent vector control are proposed for the air-gap control between the two symmetric stators and mover of the MM-PMLSM. The characteristics and control performance of the MM-PMLSM are analyzed under the concept of vector control. As a result, the proposed method is easily implemented without additional windings to control the air-gap and the mover position. The effectiveness of the proposed independent vector control algorithm is verified through experimental results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.827-828
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• 2012

WG-7 is a stream cipher based on WG Stream Cipher and is designed by Y. Luo, Q. Chai, G. Gong, and X. Lai in 2010. This cipher is designed to implement in low cost and lightweight application such as RFID tags. In this paper, we survey and compare cryptographic module such as stream and block cipher. We can estimate security performance suitable to system.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1071-1072
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• 2007

인버터 출력단은 구조상 상단락의 위험성이 내재되어있기 때문에 이를 회피하기 위한 Dead time의 적용이 반드시 요구된다. 본 논문에서는 상단락 방지기능을 갖는 출력단의 구조를 사용한 파워 모듈을 설계하고 상단락 방지기능 분석 및 Q3D Extractor와 PSPICE를 사용하여 상단락 방지형 인버터의 출력단기생임피던스의 영향을 고려한 스위칭 동작 특성을 분석하였다.

• Journal of The Korean Association of Information Education
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• v.5 no.1
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• pp.17-29
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• 2001

As the result of the rapid development of communication technology makes the circumstance and method of education change, distance education is adapted to new fields of education so that students can be educated what they need in the time and space which they want instead of relying on the existing physical frameworks. In this paper Learner-Analysing System was designed and implemented in the distance education based on the web. For the easy access and the demand of customers, this Learner-Analysing System is composed of the Q&A-processing module which can produce proper results for questions and acquisitions of their own study materials through efficient search, and the student-analyzing module for reinforcement of feedback through correct analysis.

• Journal of The Korean Association of Information Education
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• v.4 no.1
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• pp.109-119
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• 2000

In this paper, we design and implement educational system by using active database technique in www environments. The developed system consists of three modules such as user group interface, active-based monitor, and expert group interface. The roles of each module are summarized as follows. The user group interface provides with system accessibility the users who registered in the developed system. The active-based monitor, triggering modules, consists of three sub-modules such as keyword parser, exception handler, and DB access module. Also it manages five items such as keyword index, Q&A DB, user group mailing list, and expert group mailing list. The expect group interface provides answer filling form for the expert who registered in the developed system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.177-183
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• 2009

In this paper, we propose an improved anti-collision algorithm. We have designed an anti-collision unit using this algorithm for the 18000-6 Type C Class 1 Generation 2 standard (Gen2). The Gen2 standard uses a Q-algorithm for incremental method on the Dynamic Slot-Aloha algorithm. It has basically enhanced performance over the Slot-Aloha algorithm. Unfortunately, there are several non-clarified parts: initial $Q_{fp}$ value, weighted C, and the ending point of the algorithm. If an incorrect value is selected, it causes degradation in performance. Thus we propose an improved anti-collision algorithm by clearly defining the vague parts of the existing algorithm. Simulation results showed an improved performance of up to 34.8% using an optimized value of C and the initial $Q_{fp}$ value. With the ending condition, performance is 34.7%. The anti-collision unit is designed using the Verilog HDL. The module was synthesized using Synopsys' Design Compiler and the TSMC $0.2{\mu}m$ standard cell library. The synthesized result yielded 3,847 gates, and was guaranteed under the proposed working frequency of 19.2MHz.

• Archives of Plastic Surgery
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• v.45 no.4
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• pp.367-374
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• 2018

Background This analysis presents patient-reported outcomes of breast augmentation procedures performed in Singapore using an inframammary fold incision and the "5 Ps" best practice principles for breast augmentation. These data are the first of their kind in Southeast Asian patients. Methods Through a retrospective chart review, patients who underwent primary breast augmentation with anatomical form-stable silicone gel breast implants using an inframammary fold incision were followed for ${\geq}6$ months postoperatively. The BREAST-Q Augmentation Module (scores standardized to 0 [worst] - 100 [best]) and Patient and Observer Scar Assessment Scale (POSAS; 1 [normal skin] to 10 [worst scar imaginable]) were administered. Responses were summarized using descriptive statistics. Patient-reported events were collected. Results Twenty-two Southeast Asian patients (mean age, 35.1 years) completed ${\geq}1$ postoperative BREAST-Q and POSAS assessment and were assessed 11 months to 5.5 years postoperatively. The mean postoperative BREAST-Q satisfaction with breasts and psychosocial well-being scores were 69.2 and 84.0, respectively. The mean POSAS score for their overall opinion of the scar was 4.2; the mean scores for all scar characteristics ranged from 1.2 to 4.2. Over 90% of patients (20/22) said that they would recommend the procedure. Patient complaints following surgery included anisomastia (possibly pre-existing; n=2), sensory loss at the nipple (n=2) or around the nipple (n=3), scarring (n=4), and slight capsular contracture (n=1). No patients required reoperation. Conclusions Southeast Asian patients reported high long-term satisfaction scores on the BREAST-Q scale and with their scar characteristics following breast augmentation using an inframammary fold incision, and nearly all said they would recommend this procedure. No reoperations were necessary in patients assessed for up to 5.5 years postoperatively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.1
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• pp.50-55
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• 2021

Multi-path system is a system in which utilizes various networks simultaneously. It is expected that multi-path system can enhance communication speed, reliability, security of network. In this paper, we focus on path selection in multi-path system. To select optimal path, we propose deep reinforcement learning algorithm which is rewarded by the round-trip-time (RTT) of each networks. Unlike multi-armed bandit model, deep Q learning is applied to consider rapidly changing situations. Due to the delay of RTT data, we also suggest compensation algorithm of the delayed reward. Moreover, we implement testbed learning server to evaluate the performance of proposed algorithm. The learning server contains distributed database and tensorflow module to efficiently operate deep learning algorithm. By means of simulation, we showed that the proposed algorithm has better performance than lowest RTT about 20%.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.488-493
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• 2006

Accurate river discharge is the most important factor in managing river basins and for successfully maintaining total maximum daily loads in Korea. It is not easy to measure the discharge directly in large rivers owing to physical and environmental constraints, even after investing much time and money. Recently, to overcome these historical drawbacks in river discharge measurement, we have developed the Automatic Discharge Acquisition & Management System (ADAMS) that scans the river cross-section and measures each cell $(1m{\times}1m)$ velocity using HADCP. The hardware system is composed of an HADCP sensor and winch, as well as a PC and software system for the discharge calculation module and hardware control module. It is controlled remotely via the internet and uses the velocity-depth integration method and the velocity-contour method for calculating river discharges. The characteristics of ADAMS are a ubiquitously accessible system, featuring real time automatic discharge measurement, remote control via the internet. The results using ADAMS at the Jindong stage site show less than 5% uncertainty and are 4 times more efficient than the ADCP & Q-boat system. This system can be used to measure any large river, river mouth or tributary river affected by backwater, all of which have a very difficult measuring real time discharge. The next generation of ADAMS will feature an upgrade to increase portability and GPS integration.