• Journal of KIISE:Information Networking
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• v.35 no.1
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• pp.11-20
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• 2008

An inevitable trend in the next generation wireless network environments is coexistence of different wireless access networks in a complementary, manner. In addition, mobile devices equipped with multiple air interfaces simultaneously executing diverse applications have been emerging, In such network environment, It is required that a solution for mobile users to seamlessly roam between different access networks as well as to satisfy QoS requirements of each application by efficiently utilizing coexisting various wireless access networks. In this paper, therefore, we propose a mobility management platform based on per-application end-to-end mobility management and cross-layer handover controls. Four core functional modules composing the proposed platform for end user devices are defined: Monitoring Agents, Profile Database, Decision Engine, and IP Agent. We show through simulations that the presented platform provides an improved QoS as it selectively utilizes the best available networks.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.2
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• pp.207-215
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• 2004

The PLC programming by IEC1131-3 is hard to handle to ordinary users as well as professionals. Also it has not a generality, so that it couldn't be debugging some logic errors easily. In order to be adapted for such environment, In this paper, I have developed the ISPLC(Intelligent Agent System based Software Programmable Logic Controller). In ISPLC system, LD programmed by a user is converted to the C code which can be used in a commercial editor such as Visual C++. The detection of logical errors in C code is more effective than PLC programming itself. ISPLC provides the GUI-based interface in web environment and an easy programming platform to such beginners as well as professionals. The study of code conversion of LD to IL as well as IL to C is firstly tried in the world as well as KOREA. To show the effectiveness of the developed system, I applied it to a practical case, a real time traffic control system. ISPLC is minimized the error debugging and programming time owing to be supported by windows application programs.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.5
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• pp.20-27
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• 2007

In this paper, Air-interface protocols of ISO 18000-6 Type A and B applied to RFID system in UHF band are analyzed, and those algorithms are realized. Also, the improved anticollision algorithms for the Type A and B of ISO 18000-6 protocol are proposed and the performances are compared. As the results, reduction ratio of total tag recognition time of the improved ISO 18000-6 Type A algorithm is 35.2 % for 100 tags and 24.3% for 1000 tags with respect to standard algorithm, respectively. And the reduction ratio of the improved ISO 18000-6 Type B algorithm is 6.0% for 100 tags and 6.6% for 1000 tags. Therefore, the improved anticollision algorithm proposed in this paper is the advanced method improving the performance of tag recognition in the RFID system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.204-212
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• 2008

Active RFID tags are currently used in harbor transportation; they are attached to cargo containers for sea transportation. They are designed to be able to be identified by RFID readers installed at ports in many countries. The international standard ISO/IEC 18047-7 regarding RFID conformance test methods suggests the use of air interface evaluation between an RFID reader and a tag. However, the test method suggested by the international standard is intended to detect a radio signal over only a very short period. Outcomes were uncertain, making it difficult to evaluate the system accurately. This paper proposes a new evaluation method by incorporating a 'self-running test mode' environment into the RFID tags in order to reduce the test time and increase testing accuracy. We found that the application of the suggested method to actual tags improves measurement time and uncertainty over that obtained using existing methods.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.5
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• pp.53-63
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• 2019

To provide a hand gesture interface through deep learning in mobile environments, research on the light-weighting of networks is essential for high recognition rates while at the same time preventing degradation of execution speed. This paper proposes a method of real-time recognition of written characters in the air using a finger on mobile devices through the light-weighting of deep-learning model. Based on the SSD (Single Shot Detector), which is an object detection model that utilizes MobileNet as a feature extractor, it detects index finger and generates a result text image by following fingertip path. Then, the image is sent to the server to recognize the characters based on the learned OCR model. To verify our method, 12 users tested 1,000 words using a GALAXY S10+ and recognized their finger with an average accuracy of 88.6%, indicating that recognized text was printed within 124 ms and could be used in real-time. Results of this research can be used to send simple text messages, memos, and air signatures using a finger in mobile environments.

• Geophysics and Geophysical Exploration
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• v.21 no.3
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• pp.171-182
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• 2018

We performed the seismic field data processing using an open-source software (Madagascar) to verify if it is applicable to processing of field data, which has low signal-to-noise ratio and high uncertainties in velocities. The Madagascar, based on Python, is usually supposed to be better in the development of processing technologies due to its capabilities of multidimensional data analysis and reproducibility. However, this open-source software has not been widely used so far for field data processing because of complicated interfaces and data structure system. To verify the effectiveness of the Madagascar software on field data, we applied it to a typical seismic data processing flow including data loading, geometry build-up, F-K filter, predictive deconvolution, velocity analysis, normal moveout correction, stack, and migration. The field data for the test were acquired in Gunsan Basin, Yellow Sea using a streamer consisting of 480 channels and 4 arrays of air-guns. The results at all processing step are compared with those processed with Landmark's ProMAX (SeisSpace R5000) which is a commercial processing software. Madagascar shows relatively high efficiencies in data IO and management as well as reproducibility. Additionally, it shows quick and exact calculations in some automated procedures such as stacking velocity analysis. There were no remarkable differences in the results after applying the signal enhancement flows of both software. For the deeper part of the substructure image, however, the commercial software shows better results than the open-source software. This is simply because the commercial software has various flows for de-multiple and provides interactive processing environments for delicate processing works compared to Madagascar. Considering that many researchers around the world are developing various data processing algorithms for Madagascar, we can expect that the open-source software such as Madagascar can be widely used for commercial-level processing with the strength of expandability, cost effectiveness and reproducibility.

• Phonetics and Speech Sciences
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• v.11 no.1
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• pp.51-61
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• 2019

The purpose of this study was to develop a smartphone based voice therapy program for patients with voice disorders. Contents of voice therapy were collected through analysis of mobile contents related to voice therapy in Korea, experts and users' demand survey, and the program was developed using Android Studio. Content needed for voice therapy was collected through analysis of mobile contents related to voice therapy. The user satisfaction evaluation for application was conducted for five patient with functional voice disorders. The results showed that the mobile contents related to voice therapy in Korea were mostly related to breathing, followed by voice and singing, but only 13 applications were practically practiced for voice therapy. Expert and user demand surveys showed that the patients and therapists both had a high need for content that could provide voice training in places other than the treatment room. Based on this analysis, 'Home Voice Trainer', an smartphone based voice therapy program, was developed. Home Voice Trainer is an application for voice therapy and management based on Android smartphones. It is designed to train voice therapy activities at home that have been trained offline. In addition, the records of voice training of patients were managed online so that patients can maintain voice improvement through continuous voice consulting even after the end of voice therapy. User evaluations show that patients are satisfied with the difficulty and content of voice therapy programs provided by home voice trainers, but lack of a portion of user interface, such as the portion of home button and interface between screens. Further study suggests the clinical application of home voice trainer to the patients with voice disorders. It is expected that the development study and the clinical application of smart contents related to voice therapy will be actively conducted.