• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.681-687
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• 2014

Internet traffic is rapidly increasing due to the spread of personal smart devices. It causes serious burden on base stations and access points which are installed in buildings, buses, trains, and ships. We consider a communication scenario aboard a cruise ship and propose efficient contents distribution schemes to alleviate the burden of access points with multi-device-to-multi-device(MD2MD) communication. The proposed transmission method is based on the hybrid STBC-SM scheme. We compare the error performance of MD2MD communication system on the cruise ship using space-time block coding (STBC) scheme, spatial multiplexing (SM) scheme. The proposed MD2MD communication system is expected to adopt in the ship-area-network (SAN) with efficient contents distribution and reliable communication.

• Journal of the Korea Society of Computer and Information
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• v.26 no.1
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• pp.103-110
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• 2021

In this paper, we compare two access control mechanisms for D2D(Device-to-Device) systems in 5G wireless networks and propose an effective access control for 5G D2D networks. Currently, there is no specified access control for 5G D2D networks but there can be two access control approaches for 5G D2D networks. One is the UE-to-Network Relay based access control and the other is the Remote UE(User Equipment) based access control. The former is a UE-to-Network Relay carries out the access control check for 5G D2D networks but the latter is a Remote UE performs the access control check for 5G D2D networks. Through simulation and evaluation, we finally propose the Remote UE based access control for D2D systems in 5G wireless networks. The proposed approach minimizes signalling overhead between the UE-to-Network Relay and the Remote UE and more efficiently performs the access control check, when the access control functionalities are different from the UE-to-Network Relay in 5G D2D networks.

• Journal of Chest Surgery
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• v.51 no.5
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• pp.333-337
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• 2018

Background: Pinch-off syndrome (POS) is a rare complication after totally implantable venous access device (TIVAD) implantation. In cancer patients, it is important to prevent this rare complication and to recognize it early if it does occur. We present a case series of POS after TIVAD implantation and the results of a literature search about this complication. Methods: From July 2006 to December 2015, 924 permanent implantable central venous catheter implantation procedures were performed. The most common indication was vascular access for chemotherapy. Results: POS occurred in 5 patients in our clinic. Two patients experienced POS within 2 weeks, and the other 3 patients were admitted to department of surgery, Istanbul Faculty of Medicine at 6 to 14 months following implantation. The catheters were found to be occluded during medication administration, and all patients complained of serious pain. The transected fragments of the catheters had migrated to the heart. They were successfully removed under angiography with a single-loop snare. Conclusion: POS is a serious complication after TIVAD implantation. It is important to be aware of this possibility and to make an early diagnosis in order to prevent complications such as drug extravasation and occlusion events.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1103-1107
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• 2016

Network assets have been protected from malware infection by checking the integrity of mobile devices through network access control systems, vaccines, or mobile device management. However, most of existing systems apply a uniform security policy to all users, and allow even infected mobile devices to log into the network inside for completion of the integrity checking, which makes it possible that the infected devices behave maliciously inside the network. Therefore, this paper proposes a network defense mechanism based on isolated networks. In the proposed mechanism, every mobile device go through the integrity check system implemented in an isolated network, and can get the network access only if it has been validated successfully.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.575-577
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• 2013

Recently most of the hand-held smart devices have WiFi communication facility. This makes WiFi AP(access point) popular and cheaper than before. These circumstance launches some services with AP providing location based services and device control services. In this paper, we propose a AP based control system. The control system consists of AP's, AP controller and Android application program. The AP can collect MAC address information of the associated smart devices and control connected devices. The AP controller maintains DB for smart device position information and device control information. Finally Android application program provides users location based service and device control service.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.3
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• pp.11-20
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• 2018

Smart devices refer to various devices and control equipment such as health care devices, imaging devices, motor devices and wearable devices that use wireless network communication (e.g., Wi-fi, Bluetooth, LTE). Commercial services using such devices are found in a wide range of fields, including home networks, health care and medical services, entertainment and toys. Studies on smart devices have also been actively undertaken by academia and industry alike, as the penetration rate of smartphones grew and the technological progress made with the fourth industrial revolution bring about great convenience for users. While services offered through smart devices come with convenience, there is also various security threats that can lead to financial loss or even a loss of life in the case of terrorist attacks. As attacks that are committed through smart devices tend to pick up where attacks based on wireless internet left off, more research is needed on related security topics. As such, this paper seeks to design an access control method for reinforced security for smart devices. After registering and authenticating the smart device from the user's smart phone and service provider, a safe communication protocol is designed. Then to secure the integrity and confidentiality of the communication data, a management process such as for device renewal or cancellation is designed. Safety and security of the existing systems against attacks are also evaluated. In doing so, an improved efficiency by approximately 44% compared to the encryption processing speed of the existing system was verified.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.1 no.1
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• pp.1-6
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• 2007

Applying the gyroscopic technology, HeadZmouse has been developed to simulate left and right mouse click, double click, drag and drop, and even a wheel function for navigating web. This device was designed to work on both PC and Macintosh environments using a USB cable. The first time you use this device, you'll find out how much freedom it offers to someone who can't use his or her hands freely. Rather than being tied to your computer, simple manipulation such as blowing an air (breathing) into a sonic sensor can simulate all the functions which standard mouse has, even including a wheel function. Also, a macro-interface device has been developed. By storing repetitive tasks into a memory, you can carry out repetitive tasks just by clicking a button once.

• International Journal of Computer Science & Network Security
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• v.24 no.2
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• pp.178-188
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• 2024

In the near future, it is expected that there will be billions of connected devices using fifth generation (5G) network services. The recently available base stations (BSs) need to mitigate their loads without changing and at the least monetary cost. The available spectrum resources are limited and need to be exploited in an efficient way to meet the ever-increasing demand for services. Device to Device communication (D2D) technology will likely help satisfy the rapidly increasing capacity and also effectively offload traffic from the BS by distributing the transmission between D2D users from one side and the cellular users and the BS from the other side. In this paper, we propose to apply D2D overlay communication with cognitive radio capability in 5G networks to exploit unused spectrum resources taking into account the dynamic spectrum access. The performance metrics; throughput and delay are formulated and analyzed for CSMA-based medium access control (MAC) protocol that utilizes a common control channel for device users to negotiate the data channel and address the contention between those users. Device users can exploit the cognitive radio to access the data channels concurrently in the common interference area. Estimating the achievable throughput and delay in D2D communication in 5G networks is not exploited in previous studies using cognitive radio with CSMA-based MAC protocol to address the contention. From performance analysis, applying cognitive radio capability in D2D communication and allocating a common control channel for device users effectively improve the total aggregated network throughput by more than 60% compared to the individual D2D throughput without adding harmful interference to cellular network users. This approach can also reduce the delay.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.188-189
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• 2002

One of the current goals in memory device developments is to realize a nonvolatile memory, i.e., the stored information maintains even when the power is turned off. The representative candidates for nonvolatile memories are magnetic random access memory (MRAM) and ferroelectric random access memory (FRAM). In order to achieve a high density memory in MRAM device, the external magnetic field should be localized in a tiny cell to control the direction of spontaneous magnetization. (omitted)

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.271-282
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• 2015

In the business environment BYOD(Bring Your Own Device) is used and being expanded continuously. According to a survey conducted by Cisco in 2012 on 600 companies, 95% of them are already permitting the use of BYOD in their work environments so that productivity of their employees has improved as a result. Gartner predicted that the use of BYOD will be caused new security threat. They also suggested to introduce NAC(Network Access Control) to resolve this threat, to separate network zone based on importance of their business, to establish the policy to consider user authority and device type, and to enforce the policy. The purpose of this paper is to design and implement the NAC for granular access control based on IEEE(Institute of Electrical and Electronics Engineers) 802.1X and DHCP(Dynamic Host Configuration Protocol) fingerprinting, and to analyze the performance on BYOD environment.