• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.12 s.354
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• pp.40-46
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• 2006

Latching optical switches and optical logic gates AND and OR are demonstrated, for the first time, by the monolithic integration of a vertical cavity lasers with depleted optical thyristor structure, which have not only a low threshold current with 0.65mA, but also a high on/off contrast ratio more than 50dB. By simple operating technique with changing a reference switching voltage, this single device operates as two logic functions, optical logic AND and OR. The thyristor laser fabricated using the oxidation process achieved a high optical output power efficiency and a high sensitivity to the optical input light.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.74-82
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• 2015

As the complexity of an electronic device and the reduction of its operating voltage is progressing, susceptibility test of the chip and module for internal or external noises is essential. Although the immunity compliance of the chip was served with IEC 62132-4 Direct Power Injection method as an industry standard, in fact, EM immunity of the chip is influenced by their Power Domain Network (PDN). This paper evaluates the EM noise tolerance of a PLL and compares their noise transfer characteristics to the PLL on various PCB boards. To make differences of the PDNs of PCBs, various PCBs with or without LDO and with several types of capacitors are tested. For evaluation of discrepancies between EM characteristics of an IC only and the IC on real boards, the analysis of the noise transfer characteristics according to the PDNs shows that it gives important information for the design having robust EM characteristics. DPI measurement results show that greatly improved immunity of the PLL in the low-frequency region according to using the LDO and a frequency change of the PLL according to the DPI could also check with TEM cell measurement spectrum.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.253-259
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• 2011

In a ubiquitous society, the world is changing to the place where we can access to network anytime, anywhere, on any device. The mobile internet is leading the ubiquitous world and the most commonly used medium is a cell phone. However, it is uncomfortable to link to cafe, blog, and mini homepage. Because we have to stop wap service in order to upload the mobile contents like photos, videos, sound recordings produced by mobile phones. Also we have to re-access. So, in this paper content management system was designed and implemented which mobile users don't have to stop wap service in order to upload photos, videos, sound recordings produced by mobile phones. Also it supports upload in wap service integrative medicine diagnosis and contents can be managed by category.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1069-1073
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• 2016

The Internet of Things (IoT) is the interconnection of uniquely identifiable embedded computing devices within the existing Internet infrastructure. IoT is expected to offer advanced connectivity of devices, systems, and services that goes beyond machine-to-machine communications and covers a variety of protocols, domains, and applications. Key system-level features that IoT needs to support can be summarized as device heterogeneity, scalability, ubiquitous data exchange through proximity wireless technologies, energy optimized solutions, localization and tracking capabilities, self-organization capabilities, semantic interoperability and data management, embedded security and privacy-preserving mechanisms. Time information is a critical piece of infrastructure for any distributed system. Time information and time synchronization are also fundamental building blocks in the IoT. The IoT requires new paradigms for combining time and data. This paper reviews conventional time keeping mechanisms in the Internet and presents issues to be considered for combining time and data in the IoT.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.600-607
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• 2017

Virtual Reality (VR) has lately gained significant attention primarily driven by the recent market availability of consumer devices, such as mobile phone-based Head Mounted Displays (HMDs). Apart from classic gaming use cases, the delivery of $360^{\circ}$ video is considered as another major application and is expected to be ubiquitous in the near future. However, the delivery and decoding of high-resolution $360^{\circ}$ videos in desirable quality is a challenging task due to network limitations and constraints on available end device decoding and processing. In this paper, we focus on aspects of $360^{\circ}$ video streaming and provide an overview and discussion of possible solutions as well as considerations for future VR video streaming applications. This paper mainly focuses on the status of the standardization activities, Omnidirectional MediA Format (OMAF), to support interoperable $360^{\circ}$ video streaming services. More concretely, MPEG's ongoing work for OMA aims at harmonization of VR video platforms and applications. The paper also discusses the integration in MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH), which is considered as $360^{\circ}$ video streaming services with OMAF content. In context of the general OMAF service architecture.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.159-164
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• 2016

This paper proposes an improved superframe structure with one : N situation of the network as a target for efficiency battery and communication performance used in the existing standard IEEE 702.15.4 MAC layer. The proposed superframe transforms and adds a two structures. First, we add the proposed scheduling interval after the arrival of the beacon. Second, we change to a structure in which one of the contention access period is divided into two. The contention access period and the contention-free access period of active portion are divided according to the LQI value of the device. Through this system-level simulation written by $c{^+^+}$, as a results show that the battery consumption and transmission performance has been increased.

• Journal of Platform Technology
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• v.6 no.3
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• pp.17-22
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• 2018

Smart home is a technology for monitoring and controlling all the information about a house by integrating various home applications like cooling, heating, lighting, kitchen and security systems into a network. Although home appliances have become more convenient to use due to the development of smart home technology, they are also more vulnerable to information security hazards. Unauthorized visitors may have access to any of home appliance to arbitrarily control it or acquire information. This causes serious privacy and security problems, which should be solved to further smart home technology. This present paper proposed a dynamic user access control system for privacy protection in smart homes. The proposed system defines the role of a user of smart home services by automatically identifying the status information of the user and dynamically controls the access range for the service. In this way, the privacy of a user can be protected and the inter-smart device service is effectively provided. Consequently, the proposed dynamic user access control for smart home will improve the security service for protecting privacy in smart home devices.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.865-872
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• 2017

Recently, in response to the Internet age, the demand for hardware devices has been increasing, centering on the rapidly growing smart home field, due to the growth and management of sensor and control technology, mobile application, network traffic, big data management and cloud computing. In order to maintain the sustainable development of the hardware system, it is necessary to update the system, and the hardware device is absolutely necessary in real time processing of complex data (voice, image, etc.) as well as data collection. In this paper, we propose a method to simplify the control and communication method by integrating the hardware devices in two operating systems in a unified structure to solve the simultaneous control and communication method of hardware under different operating systems. The performance evaluation results of the proposed integrated hardware and the cloud control system connected to the cloud server are described and the main directions to be studied in the field of internet smart home are described.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.309-315
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• 2012

The dissemination of smartphones is being spread and supplementary services using smartphones are increasing and various as the Mobile network and device are developing rapidly, so smartphones that enables to provide a wide range of services is expected to receive the most attention. It makes users listen to music anytime, anywhere in real-time, use useful applications, and access to Internet to search for information. The service environment is changing on PC into Mobile due to the change of the circumstance mentioned above. these services are done by using just location information rather than other context, and users have to search services and use them. It is essential to have Context-aware technology for personalization recommendation services and the appropriate representation and definition of Context information for context-aware. Ontology is possible to represent knowledge freely and knowledge can be extended by inferring. In addition, design of the ontology model is needed according to the purposes of utilization. This paper used context-aware technologies to implement a user personalization recommendation service. It also defined the context through OWL modeling for user personalization recommendation service and used inference rules and inference engine for context reasoning.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.1
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• pp.55-61
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• 2016

As the price-performance ratio of embedded PCs improves, the benefits of the PC-Fi can be maximized by designing an embedded PC-Fi system. In this paper presents the design of an embedded PC-Fi that can be manipulated by a remote controller based on mobile devices such as smart phones or tablets. Additionally, an interactive control system and its GUI, through which the user can select and play music as they like at ease, are presented. The case that a large amount of music is stored in the PC-Fi system requires a function allowing the user to easily select the music they want to listen to. In order to implement this function, a DB containing detailed information of each track can be used to find the location of the desired music with keywords provided by the user. In this proposed system, the embedded PC-Fi system and remote controller are mutually connected via a WiFi network, and more than one user can remotely control the embedded system with their own mobile device.