• Journal of IKEEE
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• v.24 no.2
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• pp.378-384
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• 2020

The location information of the people or mover is essential for supporting various smart mobility services in railway stations which are mostly underground. For this purpose, a smart braille block is proposed to identify the location of the mover of the people. In this paper, the frequency characteristics of each material of the upper and lower parts of the braille block are analyzed to examine the appropriate materials for railway history. In addition, the guidelines for actual manufacturing were derived by analyzing the separation distance between two RF sensors in the smart braille block. As a result of analysis through the characteristic analysis in this paper, after selecting the material suitable for the construction site when the smart braille block is applied, the performance change of the RF system, especially the antenna that greatly influences the RF performance, must be reviewed in advance. It seems to have to be applied after checking through.

• Journal of the Korea Society for Simulation
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• v.17 no.3
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• pp.1-8
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• 2008

It is essential to maintain constant QoS despite of cell overload or erroneous wireless link during transmission because QoS of a multimedia service may be severely degraded by small delay or packet loss. This paper deals with a cell selection method for supporting the QoS of multimedia services over heterogeneous networks. The proposed scheme is based on Fuzzy Multi-Criteria Decision Making (FMCDM), in which uncertain parameters such as user system preference, the communication cost and cell load, and the transmission delay are used in the decision process using the aggregation function in fuzzy set theory. In this scheme, errors in the evaluation parameters impose milder changes on the total evaluation value than in binary logics. Simulation is focused on the average delay and packet loss rate, and the simulation results show that our proposed method provides mobile terminals the optimal performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.568-575
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• 2011

In this paper, we propose a small broadband antenna for mobile device. The proposed antenna consists of a printed rectangular monopole antenna and a parastic element connected to ground using narrow meander line and it is designed on a FR-4 substrate that has a thickness of 0.8 mm and a dielectric constant of 4.4. The FR-4 substrate's size is 50 mm${\times}$90 mm comparable to the real mobile device. The fabricated antenna's size is 12.5 mm${\times}$10.5 mm${\times}$0.8 mm and the measurement shows -10 dB return loss bandwidth of 2,200~6,000 MHz and gains of 2.86~4.01 dBi. Accordingly, the proposed antenna can support mobile device for WiBro(2,300~2,380 MHz), WLAN(IEEE 802.11b/g/n: 2,400~2,480 MHz, IEEE 802.11a: 5,150~5,825 MHz), and mobile WiMAX(IEEE 802.16e : 2,500~2,690 MHz, 3,400~3,600 MHz) service bands.

• Journal of IKEEE
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• v.24 no.3
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• pp.743-753
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• 2020

In this paper, we propose a set of robustness indicators for immersive 360-degree video. With the full-fledged service of mobile carriers' 5G networks, it is possible to use large-capacity, immersive 360-degree videos at high speed anytime, anywhere. Since it can be illegally distributed in web-hard and torrents through DRM dismantling and various video modifications, however, evaluation indicators that can objectively evaluate the filtering performance for copyright protection are required. In this paper, a robustness indicators is proposed that applies the existing 2D Video robustness indicators and considers the projection method and reproduction method, which are the characteristics of Immersive 360-degree Video. The performance evaluation experiment has been carried out for a sample filtering system and it is verified that an excellent recognition rate of 95% or more has been achieved in about 3 second execution time.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.509-512
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• 2018

최근 미세먼지에 대한 관심이 높아지고 있으며, 미세먼지를 줄이기 위한 다양한 기술이 연구되고 있다. 본 연구에서는 기존 가솔린 이륜차의 단점을 극복하고 미세먼지 발생을 줄일 수 있는 배터리 교환식 이륜차 및 IoT 기반 지원시스템을 소개한다. 전기 이륜차에 탑재되는 IoT Edge device에서는 배터리 잔량, 배터리 ID, 위치 정보 등의 정보를 LTE-M 통신을 통해 IoT 클라우드에 전송하고, 배터리 교환이 필요한 경우 주변의 배터리 교환기 위치 및 교환 가능한 배터리 정보 전달 받을 수 있다. 현재 전기이륜차에 탑재될 IoT Edge device 및 사용자용 스마트폰앱을 개발하고 있으며, 배터리 교환기 및 클라우드 서비스 개발도 수행될 예정이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.675-677
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• 2013

IT ecosystem is changing with the spread of smart devices and thus, cloud computing fields have been issued to companies. Cloud computing reduces IT costs and aims for eco-friendly Green IT. It also supports all kinds of IT equipment so you can conduct business in real time when moving. With these advantages, many corporations are considering cloud computing but there are security issues when implementing cloud. In this paper, we analyze security problems of clouding service and present the appropriate guidelines. This will be utilized in the fields of cloud computing and service delivery.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.791-798
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• 2015

It has been grown interests of the convergence technologies about communication systems and vehicular industry. Vehicular communications enable a number of infotainment applications to serve cars under high mobility environments. To achieve this goal, a robust and accurate channel estimation scheme is of great importance. This paper proposes an enhanced Decision-Directed channel estimation scheme called PTAU(Pilot Tone Aided Update) for IEEE 802.11p in vehicular communication environment. Existing approaches which use subsequent data symbols to estimate channel response in time domain will lead to the error propagation. In this paper, we use the pilot subcarriers to get initial channel response, then utilize the correlation characteristics to update channel response in frequency domain. Finally, Analysis and simulation results reveal that the proposed scheme outperforms in bit error rate(BER), significantly improve the performance of the estimation.

• Journal of IKEEE
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• v.19 no.2
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• pp.133-141
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• 2015

The IMS is an architectural control framework for delivering IP multimedia services such as voice, video, audio and data, the IMS supports not only the mobile communication system but also the existing wired and wireless network based on IP. The network that is integrated by the IMS needs policy-based network management protocol for managing the limited network resources to provide efficient multimedia service. The IMS use additional device called PDF for efficient resource management, but the PDF only uses diameter which is one of the network management protocol such as SNMP and COPS. Many devices use various protocol to manage the limited network resources. There is an algorithm using a variety of protocols such as Diameter, COPS and SNMP to handle the resources management efficiently. We also analyze the performance using the proposed algorithm in the implemented IMS environment.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.5
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• pp.311-318
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• 2013

Recently, there have been many studies on RFID-based SCM. Yet, studies of synchronizing errors caused by tracking logistics information in supply chain, and activating & monitoring RFID infra is still insufficient. Also, there is no case of developing the intelligent SCM system enabling total monitoring and controlling RFID Infra by applying these technologies. Logistics information synchronization based Smart SCM model is intelligent supply chain service model to monitor the status of the RFID equipments in supply chain and the synchronization of the logistics process in each logistics point through one integrated view, as well as to react instantly by providing the information to help the various decision makings, when the emergency occurs. By adopting global logistics standard, RFID related standard specification, EPCIS standard, and SSI middleware platform, this model provides the domestic standard specification.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.631-640
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• 2009

The highest priority of the cruise trip is the safety and comfort of its passengers. Though the cruise lines take every appropriate measure to ensure that their Passengers are safe and experience enjoyable vacations it is hard to fulfill all passenger's personnel requirement with limited number of crews. Generally, each passenger is issued an identification card which contains their digital photo and personal identification information on a magnetic strip that he or she must present when entering or leaving the ship. This technology allows the ship to know which Passengers and crew members are on board and which are not. However, this system has some limitations of functions and usage. To support each passenger as his or her personal liking, additional number of crews or some kind of new system is needed. In this paper, the crew support system based on sensor network using wireless and wired communication technologies was studied. To design the system, PLC(Power Line Communication) system and ZigBee based passenger location recognition, classification system has studied experimentally. By using this system, crews can serve passengers more closely and personally with less effort.