• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.7 s.361
• /
• pp.62-70
• /
• 2007

In this paper, we design a mobile camera processor to support the MIPI CSI-2 and DPHY specification. The lane management sub-layer of CIS2 handles multi-lane configuration. Thus conceptually, the transmitter and receiver have each independent buffer on multi lanes. In the proposed architecture, the independent buffers are merged into a single common buffer. The single buffer architecture can flexibly manage data on multi lanes though the number of supported lanes are mismatched in a camera processor transmitter and a host processor. For a key issue for the data synchronization problem, the synchronization start codes are added as the starting for image data. We design synchronization logic to synchronize the received clock and to generate the byte clock. We present the verification results under proposed test bench. And we show the waves of simulation and logic synthesis results of the designed processor.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.3
• /
• pp.391-398
• /
• 2018

There are many problems caused by data sharing between general heterogeneous digital devices due to various interfaces. To solve this problem, this paper proposes heterogeneous data sharing with cloud service and mobile through D2D communication that supports communication between different devices. The proposed technique is used to reduce the load on the server to perform data synchronization. Also, in order to minimize data latency caused by data replication between different devices, a technique to enhance the speed of data writing with copying only the modified parts in the chunk list is adopted and cloud service model integrated with mobile environment is realized in order to minimize the network bandwidth consumed for synchronization for data sharing. Therefore, it is possible to share data in different spaces efficiently with maintaining data integrity and minimizing latency in data.

• Journal of Korea Multimedia Society
• /
• v.10 no.5
• /
• pp.623-630
• /
• 2007

With the development in IT technology and with growing demands of users, a ubiquitous environment is being made. Because of individuals identification is important in ubiquitous environment, RFID, a technology used frequently. RFID, a technology that radio frequency identification, reader send signer, then tag provide user information. RFID has various strengths, such as high recognition rates, quick recognition speed, but Eavesdropping is possible and problem that user information is revealed happens. To solve this, study is proceeded with activity, but, because of low-cost passive tag is limited operation capability, usually used hash function and random number. Also updates value that is used to present session and uses in next session. Therefore, this scheme protects user privacy using random number. And this sheme can offer synchronization by creating variable value without updating value.

• Smart Media Journal
• /
• v.8 no.3
• /
• pp.41-46
• /
• 2019

In a MMORPG, a typical application of virtual environment systems, it is a common desire to play in a more realistic environment. However, it is very difficult to provide a latency-free virtual environment to a large user base, mainly due to the fact that the real environment must be configured on multiple servers rather than on single server and that data must be shared on the real server when users move from one region to another. Experiencing response delays continuously in the process of information synchronization between servers greatly deteriorates the degree of immersion. In order to solve this problem, it is necessary to minimize the response delay occurring in the information synchronization process between the servers. In this paper, we propose Migration Agent for efficient information synchronization between field servers providing information of virtual environment and minimizing response delay between Field Server and PC(Player Character) and implement it in cloud computing network. In the proposed system, CPU utilization of field server increased by 6 ~ 13%, and response time decreased by 5 ~ 10 seconds over the existing system in 70,000 ~ 90,000 PCs

• The Journal of the Acoustical Society of Korea
• /
• v.9 no.2
• /
• pp.61-69
• /
• 1990

We have investigated the digital bit synchronization problem in baseband communication receiver systems using the Gauss-Markov estimation technique which is equivalent to the weighted least square method. The realized bit synchronizer, including the data detector, processes the input signal two dimensionally into the transition phase and data level under the white Gaussian noise environment. We have confirmed the relization of the bit synchronizer via computer simulation. In addition, we have compared and evaluated the estimation error performance of the proposed method with that of the conventional DTTL method and of the minimum likelihood method.

• Journal of Korea Society of Industrial Information Systems
• /
• v.22 no.3
• /
• pp.27-38
• /
• 2017

This Paper Presents a Method for Stitching a Large Number of Images Recorded by a Large Number of Individual Users Through a Cellular Phone Camera at a Venue. In Contrast to 360 Camera Solutions that Use Existing Fixed Rigs, these Conditions must Address New Challenges Such as Time Synchronization, Repeated Transformation Matrix Calculations, and Camera Sensor Mismatch Correction. In this Paper, we Solve this Problem by Updating the Transformation Matrix Using Time Synchronization Method Using Audio, Sensor Mismatch Removal by Color Transfer Method, and Global Operation Stabilization Algorithm. Experimental Results Show that the Proposed Algorithm Shows better Performance in Terms of Computation Speed and Subjective Image Quality than that of Screen Stitching.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.7
• /
• pp.1792-1801
• /
• 2012

Symbol timing error amounts to a major degradation in the system performance. Conventionally, timing error is estimated by predefined preamble on both transmitter and receiver. The maximum of the correlation result is considered the start of the OFDM symbol. Problem arises when the prime path is not the strongest one. In this paper, we propose a new combined time and channel estimation method for multi-band OFDM ultra wide-band (MB-OFDM UWB) systems. It is assumed that a coarse timing has been obtained at a stage before the proposed scheme. Based on the coarse timing, search interval is set (or time candidates). Exploiting channel statistics that are assumed to be known by the receiver, we derive a maximum a posteriori estimate (MAP) of the channel impulse response. Based on this estimate, we discern for the timing error. Timing estimation performance is compared with the least squares (LS) channel estimate in terms of mean squared error (MSE). It is shown that the proposed timing scheme is lower in MSE than the LS method.

• Journal of Advanced Navigation Technology
• /
• v.15 no.5
• /
• pp.722-728
• /
• 2011

Most services need to have authentication protocols to verify users' eligibility in the network environment. For this, a lot of user authentication protocols have been researched and developed. Two of them, SPMA and I-SPMA protocols, introduced the lack of mutual authentication and vulnerability to the reply attack of the prior protocols and suggested revised protocols. Nevertheless, these protocols did not mention about the critical problem caused when the server and the client lose synchronization on the secret information between them. Therefore, in this paper, we analyze the security characteristics of the existing protocols and prove the vulnerability to the synchronization of the protocols.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.6
• /
• pp.1242-1249
• /
• 2012

This paper proposes a metastability-free synchronization method and a mesochronous synchronizer for NoC. It uses the clock transmitted from TX as a strobe and solves the metastability problem by selecting one of rising or falling clock edge depending on the sampling value in RX when the phase difference between clocks is under a metastability window. The logic simulation results show that it works without metastability under $0^{\circ}{\sim}360^{\circ}$ phase difference in the synchronizer that a fault is inserted. The mesochronous synchronizer has a simple control logic and is suitable for NoC.

• 한국정보통신설비학회:학술대회논문집
• /
• 2006.08a
• /
• pp.57-61
• /
• 2006

As high speed internet users are tremendously increasing, three are keenly in need of development of high speed portable internet technology which can provide high quality wireless internet service cheaply even in the mobile. Unlike the FDD-CDMA, TDD-OFDMA has relatively poor wave environment with inducing interference, fading and delay because it agrees to multi-carrier modulation method and time-division radio telecommunication system. To solve this problem, it is necessary to develop repeater operating by digital signal processing method which have more strict wireless channel control and wave signal processing technology over TDD telecommunication equipments. This thesis is dealing with design and implementation of Digital RF Repeater which implemented 'Synchronization Acquisition Unit', 'TDD signal switching Unit', 'Feedback Signal Cancellation Unit'. Over this argument, we will develop digital RF repeater with more cheap, more adaptive in wave environment like oscillation control, adaptive wave monitoring and output increasing and having control function as a result it will be helpful for success in high speed portable internet service business.