• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.516-519
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• 2011

현재 모바일 폰은 실시간 운영체제를 구동하는 CP(Communication Processor)와 범용 운영체제를 구동하는 AP(Application Processor}, 두 개의 프로세서를 사용하고 있다 임베디드 가상화는 하나의 칩 위에 실시간 운영체제와 범용 운영체제를 동시에 동작시킬 수 있는 솔루tus을 제공하면서, 각각의 운영체제가 서로 고립되어 동작하도록 한다. 따라서 임베디드 가상화 솔루션을 모바일 폰에 적용하면 하나의 집을 사용하여 비용을 절약하면서, 하이퍼바이저 위에 고립된 각각의 운영체제를 구동할 수 있기 때문에 각광을 받고 있다. Xen-ARM 은 모바일 기기에서 가장 많이 사용되는 ARM 프로세서에서 동작하는 하이퍼바이저로 임베디드 기기의 탑재를 목적으로 개발되었다. 그러나 현재의 Xen-ARM의 크레딧 스케쥴러는 CPU 공평성에 포커스를 맞추고 있어 실시간 IO를 제한된 시간 안에 처리할 수 없기 때문에, 실시간 IO를 처리해야 하는 임베디드 기기에 적용하기 어렵다. 본 논문에서는 현재 Xen-ARM이 실시간 IO를 지원할 수 없는 것을 실험을 통해 보여주고, 실시간 IO를 지원하기 위한 방안을 제시한다. 또한 수정된 Xen-ARM을 모바일 폰에 적용하는 방안에 대해 제시한다.

• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.45-51
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• 2018

In this paper, we propose a Designed and Developed home router management system. Through the fourth industrial revolution and development of IoT technology, now people can experience a wide range of IoT related services at their workplace or daily lives. At the industrial site, IoT devices are used to improve productivity such as factory automation, and at home, IoT technology is used to control home appliances from a remote distance. Usually IoT device is integrated and controlled by the router. Home router connects different IoT devices together at home, however when security issues arise, it can invade personal privacy. Even though these threats exist, the perception for home router security is still insufficient. In this paper, we have designed and developed home router management system using DEVS methodology to promote the safe use of home router. Through the DEVS methodology, we have designed the system and developed the mobile application. This management system enables users to set up security options for home router easily.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.515-517
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• 2003

In this paper we examine the effects of the required portions of guard timing spaces in a MAC frame of ETSI BRAN HIPERLAN/2 system such as inter-mobile guard timing space in UL(Up Link) duration, inter-RCH(Random CHannel) guard timing space, sector switch guard timing space. In particular, we calculate the number of OFDM(Orthogonal Frequency Division Multiplexing) symbols required for these guard timing spaces in a MAC frame. We them evaluate the throughput of HIPERLAN/2 system as we vary parameter such as the guard time values defined in [2], the number of DLCCs(Data Link Control Connections), and the number of RCHs. Finally we show by numerical results that the portions for the 새심 summation of required guard timing spaces in a MAC frame are not negligible, and that they should be properly considered when trying to evaluate the performance of MAC protocol of HIPERLAN/2 system and also when determining the number of RCHs as well as the number of DLCCs in UL PDU trains at an AP/CC(Access Point/Central Controller).

• Journal of the Microelectronics and Packaging Society
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• v.29 no.1
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• pp.1-6
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• 2022

The mobile device industry demands much higher levels of integration and lower costs coupled with a growing awareness of the complete system's configuration. A subsystem module package is similar to a board-level circuit that integrates a system function in a package beyond a System-in-Package (SiP) design. It is an advanced IC packaging solution to enhance the PDN and achieve a smaller form factor. Unlike a system-level design with a decoupling capacitor, a subsystem module package system needs to redefine the role of the capacitor and its configuration for PDN performance. Specifically, the design of package's form factor should include careful consideration of optimal PDN performance and the number of components, which need to define the decoupling capacitor's value and the placement strategy for a low impedance profile with associated cost benefits. This paper will focus on both the static case that addresses the voltage (IR) drop and AC analysis in the frequency domain with three specific topics. First, it will highlight the role of simulation in the subsystem module design for the PDN. Second, it will compare the performance of double-sided component placement (DSCP) motherboards with the subsystem module package and then prove the advantage of the subsystem module package. Finally, it will introduce three-terminal decoupling capacitor (decap) configurations of capacitor size, count and value for the subsystem module package to determine the optimum performance and package density based on the cost-effective model.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.2
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• pp.73-81
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• 2024

Recently, mobile manipulators have been utilized in agriculture industry for weed removal and harvest automation. This paper proposes a domain adaptive fruit detection method for harvest automation, by utilizing OWL-ViT model which is an open-vocabulary object detection model. The vision-language model can detect objects based on text prompt, and therefore, it can be extended to detect objects of undefined categories. In the development of deep learning models for real-world problems, constructing a large-scale labeled dataset is a time-consuming task and heavily relies on human effort. To reduce the labor-intensive workload, we utilized a large-scale public dataset as a source domain data and employed a domain adaptation method. Adversarial learning was conducted between a domain discriminator and feature extractor to reduce the gap between the distribution of feature vectors from the source domain and our target domain data. We collected a target domain dataset in a real-like environment and conducted experiments to demonstrate the effectiveness of the proposed method. In experiments, the domain adaptation method improved the AP50 metric from 38.88% to 78.59% for detecting objects within the range of 2m, and we achieved 81.7% of manipulation success rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.33-43
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• 2010

Recently, users want to use real-time multimedia services, such as internet, VoIP, etc., using their IEEE 802.11 wireless lan mobile stations. In order to provide such services, a handoff among access points is essential to support the mobility of a node, in such an wide area. However, the legacy handoff methods of IEEE 802.11 technology are easy to lose connections. Also, the recognition of a disconnection and channel re-searching time make the major delay of the next AP to connect. In addition, because IEEE 802.11 decides the selection of an AP depending only on received signal strength, regardless of a node direction, position, etc., it cannot guarantee a stable bandwidth for communication. Therefore, in order to provide a real-time multimedia service, a node must reduce the disconnection time and needs an appropriate algorithm to support a sufficient communication bandwidth. In this paper, we suggest an algorithm which predicts a handoff point of a moving node by using GPS location information, and guarantees a high transmission bandwidth according to the signal strength and the distance. We implemented the suggested algorithm, and confirmed the superiority of our algorithm by reducing around 3.7ms of the layer-2 disconnection time, and guaranteed 24.8% of the communication bandwidth.

• Journal of radiological science and technology
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• v.45 no.4
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• pp.299-304
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• 2022

This study uses the 'S-align' function to present a reference value of the X-ray tube angle for the realization of an image similar to that of the chest PA image during chest AP radiography. This study targeted dummy phantom and used a 17"×17" DR image receptor. The irradiation conditions were 110 kVp, 160 mA, 50 ms, and the distance between the central X-ray and the image receptor was set to 180 cm and 110 cm, respectively. The end of the catheter was placed at the 11th thoracic height to indicate the nasogastric tube. In the case of lung apex length measurement, the mean value of measurement was 30.53±0.47 in PA. T 0°, TCA 5~25°, TCE 5~15° were 21.07±0.29, 27.60±0.21, 34.13±0.44, 39.86±0.31, 45.96±0.61 mm, 54.13±0.37 mm, 16.16±0.46 mm, 9.81±0.35 mm, 2.75±0.30 mm, respectively. For the depth of the catheter end, the average value measured at PA was 6.70±0.31 mm. T 0°, TCA 5~25°, TCE 5~15° were 15.72±0.38 mm, 24.10±0.50 mm, 29.24±0.86 mm, 34.35±0.35 mm, 41.06±1.08 mm, 48.07±0.38 mm, 12.85±0.25 mm, 7.92±0.36 mm, 3.01±0.39 mm, respectively. The length of the lung apex was similar to that of chest PA when the angle of incidence was adjusted from 5° to 10° in the leg direction, and the depth of the catheter tip was most similar when the X-ray tube angle was incident at 10° in the head direction. Therefore, To change the X-ray tube angle according to the purpose of the examination during the chest AP radiography using 'S-align' function is considered necessary.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2345-2351
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• 2013

LBS(Location Based System) usually uses GPS technology to measure the exact position of the moving object. However, the method of managing location which utilizes the WiFi technology of mobile phone has not been introduced so far. The method of managing moving objects in view of the location of guardian has also not been proposed. In this paper, a new location management system of moving objects which take guardian's location into consideration is proposed. Specifically, the three methods of searching for missing child proposed in this paper are as follows : 1) a method based on an app for smart phone, 2) a method based on control server, 3) a method based on control server and fixed APs. Because the proposed system reflects the location of the guardian, the guardian is able to identify the state of child immediately and the workload can be reduced.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.305-312
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• 2007

In this paper, we present a received signal strength (RSS) prediction model to timely Initiate link layer triggers for fast handoff in a wireless LAN system. Noting that the distance between a mobile terminal and an access point is not changed abruptly in a short time interval, an adaptive RSS predictor based on a stationary time series model is proposed. RSS data obtained from ns-2 simulations are used to identity the time series model and verify the predictability of the RSS data. The results suggest that an autoregressive process of order 1 (AR(1)) can be used to represent the measured RSSs in a short time interval and predict at least 1-step ahead RSS with a high confidence level.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2177-2184
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• 2012

A different and effective method for indoor positioning system is needed and increased it's importance compare to the outdoor GPS based method. The FingerPrint positioning method is known as a superior method in indoor positioning system that maintains signal strength patterns for RPs(Reference Points) in database and compare the DB with the measured real-time signals on the mobile device. FingerPrint positioning method is necessary to establish an accurate database, but errors can occur by several factors. In this paper, we analyze the signal patterns of each terminal in accordance with connection state of access point and trace that the error in accordance with connection state of access point can be an important error in FingerPrint DB configuration through an experimental case study.