• Design & Manufacturing
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• v.13 no.3
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• pp.19-23
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• 2019

In the mold industry, CAM software has been introduced to solve the impossible or time-consuming part of the mold industry because the increase in labor costs, the drop in mold price, and the short delivery time are tasks to be solved not only in the manufacturing industry but also in the mold industry as a whole. In order to reduce the processing time and improve the surface roughness, we have been conducting various researches for efficient machining. This study was carried out to compare the ball end mill and radius end mill tools with the Power mill software and NC brain software under the same conditions and to find out the most efficient method of machining the smooth drafting surface and improving the surface roughness. (1) By machining the smooth drafting surface using radius end mill, the machining time is 23.7% faster than when using ball end mill. (2) Surface roughness when machined with radius end mill is smoother than when using ball end mill. Based on these results, it can not be applied to all shapes, but if it is a relatively wide and simple gradient shape, the raster machining method using radius end mill can be more effective in terms of delivery and quality than machining with ball end mill.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1173-1176
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• 2000

본 논문은 화상회의 시스템 개발에 있어서 양방향 흐름제어 방식을 제안한다. 제안한 양방향 흐름 제어 방식은 End-To-End 간의 처리량과 네트워크의 상태를 SR과 RR의 손실율을 이용해서 3가지 상태(혼잡, 안정, 무부하)로 정의하였으며 그에 따른 양방향 흐름 제어 알고리즘을 적용해서 전송율을 조절해서 손실율을 줄이고 양단간 처리량 증가 및 송수신의 공정성을 갖게 한다. 제안한 알고리즘을 적용해 PC 카메라를 이용한 화상회의 시스템을 구현했으며, 이를 통해서 양측 모두 손실율의 감소, 수신율의 증가, 안정적인 송.수신, 송.수신량의 공평성이 향상되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1239-1242
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• 2000

인터넷 우편 시스템은 기존의 우편시스템을 인터넷이라는 공용 망을 이용해서 재구성함으로서 우체국 업무의 효율성은 무론, 사용자의 편이에도 상당한 도움이 될 것이다. 인터넷 우편 시스템은 크게 3가지로 Front Agent(웹 기반의 사용자 인터페이스), End Agent(우체국). Management Agent(관리부) 나뉘어 지는데 본 논문에서는 End Agent를 중심으로 서술하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.1008-1011
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• 2015

본 연구는 디지털 컨텐츠를 판매하는 쇼핑몰에서 각 컨텐츠에 대해서 개별적으로 신용카드 기반으로 결제/판매할 수 있도록 하는 시스템이다. 이를 위해 본 연구에서는 PHP 기반 쇼핑몰 전반부(front-end)와 Spring MVC 기반 쇼핑몰 후반후(Back-end)를 분리하여 구현하였다. 전반부에서는 기본적으로 판매되는 각 디지털 컨텐츠를 분류별로 보여주는 기능을 구현하였고, 후반부에서는 각 디지털 컨텐츠에 대한 상세정보를 보여주며 신용카드 결제/IP 기반 접속제한/로깅(logging) 기능 등을 제공하도록 하였다. 특정 디지털 컨텐츠를 온라인으로 결제시에는 그로부터 24시간내에는 몇 번이고 다운로드 할 수 있도록 서비스 하기 위해서, E-rnail을 통한 인증코드(access code)를 제공하는 기능도 구현하였다. 또한, 이러한 구현을 Spring MVC 3.0 기반 구조에 의거하여 구현함으로써, 향후 시스템 유지보수성을 획기적으로 향상시켰다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.435-437
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• 2022

보행 보조 로봇의 효과적인 보조를 위해서는 사용자의 보행 유형을 인식하는 것이 중요하다. 본 논문에서는 end-to-end 분류 네트워크 기반 보행 환경 인식 방법을 사용하여 사용자의 보행 유형을 강인하게 추정한다. 실외 보행 환경을 오르막길, 평지, 내리막길 3 가지로 분류하는 딥러닝 모델을 학습시켰으며, 엣지 디바이스에서 이를 사용하기 위해 네트워크 경량화를 진행하였다. 경량화 후 추론 속도는 약 47FPS 수준으로 실시간으로 보행 보조 로봇에 적용 가능한 것을 검증했으며, 정확도 측면에서도 97% 이상의 성능을 얻을 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.2001-2011
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• 1993

This study deals with the machining of sculptured surfaces on 5-axis CNC milling machine with end mill cutter. The study (I) has the following contents. In 5-axis CNC milling, CL-data consist of CC-data and cutter axis direction vector at the CC-point. Thus, in machining of the sculptured surface on 5-axis CNC milling machine, determination of the direction vector of the milling cutter is very important. The direction vector is obtained by the fact that bottom plane of the milling cutter must not interfere with the free-form surface being machined. The interference is checked by the z-map method which can be applied in all geometric types of the sculptured surfaces. After generating NC part programs from 5-axis post-processing algorithms, sculptured surfaces were machined with 5-axis CNC milling machine (CINCINNATI MILACRON, 20V-80). From these machining tests, it was shown that the machining of the free-form surfaces on 5-axis CNC milling machine with the end mill has smaller cusp heights and shorter cutting time than on 3-axis CNC milling machine with the ball-end mill. Thus, 5-axis CNC end milling was effective machining method for sculptured surfaces. The study (II) deals with the prediction of cusp height and the determination of tool path interval for the 5-axis machining of sculptured surfaces on the basis of study(I).

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.3
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• pp.158-167
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• 2017

Internet-based social and interactive video applications have become major constituents of the envisaged applications for next-generation multimedia networks. However, inherently dynamic network conditions, together with varying user expectations, pose many challenges for resource allocation mechanisms for such applications. Yet, in addition to addressing these challenges, service providers must also consider how to mitigate their operational costs (e.g., energy costs, equipment costs) while satisfying the end-user quality of service (QoS) expectations. This paper proposes a heuristic solution to the problem, where the energy incurred by the applications, and the monetary costs associated with the service infrastructure, are minimized while simultaneously maximizing the average end-user QoS. We evaluate the performance of the proposed solution in terms of serving probability, i.e., the likelihood of being able to allocate resources to groups of users, the computation time of the resource allocation process, and the adaptability and sensitivity to dynamic network conditions. The proposed method demonstrates improvements in serving probability of up to 27%, in comparison with greedy resource allocation schemes, and a several-orders-of-magnitude reduction in computation time, compared to the linear programming approach, which significantly reduces the service-interrupted user percentage when operating under variable network conditions.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.375-384
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• 2002

In the current Internet, the QoS of interactive applications is hardly guaranteed because of variable bandwidth, packet loss and delay. Moreover, VoIP which is becoming an important part of the information infra-structure in these days, is susceptible to network packet loss and end-to-end delay. Therefore, it needs error control mechanisms in network level or application level. The FEC-based error control mechanisms are used for interactive audio application such as VoIP. The FEC sends a main information along with redundant information to recover the lost packets and adjusts redundant information depending on network conditions to reduce the bandwidth overhead. However, because most of the error control mechanisms do not consider end-to-end delay but packet loss rate, their performances are poor. In this paper, we propose a new error control algorithm, SCCRP, considering packet loss rate as well as end-to-end delay. Through experiments, we confirm that the SCCRP has a lower packet loss rate and a lower end-to-end delay after reconstruction.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.38-48
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• 2014

In this paper, a design of Signal Processing Analog Front-End IC for Automotive Piezo-Resistive Type Pressure Sensor is presented. In modern society, as the car turns to go from mechanical to electronic technology, the accuracy and reliability of electronic parts required importantly. In order to improve these points, Programmable Gain Amplifier (PGA) amplifies the received signal in accordance with gain for increasing the accuracy after PRT Sensor is operated to change physical pressure signals to electrical signals. The signal amplified from PGA is processed by Digital blocks like ADC, CMC and DAC. After going through this process, it is possible to determine the electrical signal to physical pressure signal. As processing analog signal to digital signal, reliability and accuracy in Analog Front-End IC is increased. The current consumption of IC is 5.32mA. The die area of the fabricated IC is $1.94mm{\times}1.94mm$.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.190-191
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• 2014

Out-of-Order Packet ($O^3P$) problem is an issue that significantly impacts to the QoS of service and network. Route optimization (RO) in PMIPv6 is proposed by P.Loureiro and M. Liebsch to reduce the load of LMAs and transmission delay. In RO scheme, at the time the optimal path is established, there exist two paths: optimal path and old path as non-optimal path for transmitting data between MN1 and MN2 that is the cause of $O^3P$ occurring. This paper proposes a scheme to prevent $O^3P$ problem by using packet buffering technique and a new mobility message, named End Traffic Marker (ETM) to mark the end of packet delivery through the old path.