An efficient synchronization scheme of multimedia streams in wireless and mobile systems

Recent advances in mobile computing and distributed multimedia systems allow mobile hosts (clients) to access wireless multimedia systems anywhere and at anytime, but not without creating a new set of issues and trade-offs. To the best of our knowledge, there has been very little research in dealing with the synchronization problem in wireless and mobile multimedia systems. In this paper, we propose an efficient distributed synchronization algorithm using quasi-sink for wireless and mobile multimedia systems to ensure and facilitate mobile client access to multimedia objects. We discuss the algorithm and provide its proof of correctness. We also present a set of simulation experiments to evaluate the performance of our scheme using message complexity and buffer usage at each frame arrival time. Our results indicate that our scheme exhibits a significant low message complexity and no underflow and overflow within the bounded delivery time.     

A Distributed Algorithm for Dynamic Channel Allocation

Recent demand for mobile telephone service has been growing rapidly while the electro-magnetic spectrum of frequencies allocated for this purpose remains limited. Any solution to the channel assignment problem is subject to this limitation, as well as the interference constraint between adjacent channels in the spectrum. Channel allocation schemes provide a flexible and efficient access to bandwidth in wireless and mobile communication systems. In this paper, we present an efficient distributed algorithm for dynamic channel allocation based upon mutual exclusion model, where the channels are grouped by the number of cells in a cluster and each group of channels cannot be shared concurrently within the cluster. We discuss the algorithm and prove its correctness. We also show that the algorithm requires at most (worst case) O(N _gN _n logN _n) messages, where N _g is the number of groups and N _n is the number of neighbors. This is compared to Choy's algorithm which requires O(N _g ²N _n), where N _g is the number of groups and N _n is the number of neighboring cells in the system. We report our algorithm's performance with several channel systems using different types of call arrival patterns. Our results indicate that significant low denial rate, low message complexity and low acquisition time can be obtained using our algorithm.     

Watermarking two dimensional data object identifier for authenticated distribution of digital multimedia contents

A digital object identifier refers to diverse technologies associated with assigning an identifier to a digital resource and managing the identification system. One type of implementation of a digital object identifier developed by the Korean Government is termed the Universal Content Identifier (UCI) system. It circulates and utilizes identifiable resources efficiently by connecting various online and offline identifying schemes. UCI tags can contain not only identifiers but also abundant additional information regarding contents. So, researchers and practitioners have shown great interest in methods that utilize the two-dimensional barcode (2D barcode) to attach UCI tags to digital contents. However, attaching a 2D barcode directly to a digital content raises two problems. First, quality of the content may deteriorate due to the insertion of the barcode; second, a malicious user can invalidate the identifying tag, simply by removing the tag from the original content. We believe that these concerns can be mitigated by inserting an invisible digital tag containing information about an identifier and digital copyrights into the entire area of the digital content. In this study, to protect copyrights of digital contents securely without quality degradation, we attempt to discover a sequence of process for generating a 2D barcode from a UCI tag and watermarking the barcode into a digital content. Such a UCI system can be widely applied to areas such as e-learning, distribution tracking, transaction certification, and reference linking services when the system is equipped with 2D barcode technology and secure watermarking algorithms. The latter part of this paper analyzes intensive experiments conducted to evaluate the robustness of traditional digital watermarking algorithms against external attacks.     

Network slicing as enablers for 5G services: state of the art and challenges for mobile industry

Telecommunication Systems - The next generation of mobile communications, 5G, is expected to enable global economic output of USD 12.3 trillion by 2035. This would be achieved by applying 5G...     

Examining success factors in the adoption of digital object identifier systems

Systems for identifying and managing digital objects are becoming essential for digital content providers as the growth of the digital content market accelerates. Not much research has been done to examine the successful adoption of digital object identifier systems. This study examines the success factors for the adoption of digital object identifier systems by extending DeLone and McLean’s information systems success model. A large-scale field study targeting digital content providers in Korea was employed to empirically validate a research model. Data was collected from 120 respondents from 41 digital content providers. The results indicate that information quality is the strongest factor to influence organizational benefits through perceived usefulness and user satisfaction. The syndication efforts of digital content providers can be a moderator in the successful adoption of digital object identifier systems. This has implications for how practitioners can best communicate the features and benefits of digital object identifier systems and provides additional support for researchers to examine the underutilized construct of organizational benefit. Limitations of this study are discussed in addition to concluding remarks.     

Heterofermentative lactic acid bacteria dominate in Korean commercial kimchi

Food Science and Biotechnology - Lactic acid bacterial communities in kimchi prepared by representative Korean kimchi companies were investigated using a pyrosequencing method. The pH values of 9...     

Analyzing the Economic Effects of Past Mobile Network Sharing Deals for Future Network Deployment

The increase in data traffic calls for investment in mobile networks; however, the saturating revenue of mobile broadband and increasing capital expenditure are discouraging mobile operators from investing in next-generation mobile networks. Mobile network sharing is a viable solution for operators and regulators to resolve this dilemma. This research uses a difference-in-differences analysis of 33 operators (including 11 control operators) to empirically evaluate the cost reduction effect of mobile network sharing. The results indicate a reduction in overall operating expenditure and short-term capital expenditure by national roaming. This finding implies that future technology and standards development should focus on flexible network operation and maintenance, energy efficiency, and maximizing economies of scale in radio access networks. Furthermore, mobile network sharing will become more viable and relevant in a 5G network deployment as spectrum bands are likely to increase the total cost of ownership of mobile networks and technical enablers will facilitate network sharing.     

TEE based session key establishment protocol for secure infotainment systems

Most vehicles are now produced with infotainment features. However, as reported in various security conferences, security vulnerabilities associated with an infotainment system can cause serious security issues, e.g., an attacker can control in-vehicle systems through the infotainment system. To address such security issues, in this paper, we propose a session key establishment protocol using Elliptic Curve Cryptography. The proposed protocol enables secure authentication and key distribution between a user device and a telematics control unit. We also shows how a trusted execution environment is used for the proposed protocol. We present detailed protocol operations with conducted security analysis results.     

Learning dispatching rules using random forest in flexible job shop scheduling problems

In this paper, we address the flexible job-shop scheduling problem (FJSP) with release times for minimising the total weighted tardiness by learning dispatching rules from schedules. We propose a random-forest-based approach called Random Forest for Obtaining Rules for Scheduling (RANFORS) in order to extract dispatching rules from the best schedules. RANFORS consists of three phases: schedule generation, rule learning with data transformation, and rule improvement with discretisation. In the schedule generation phase, we present three solution approaches that are widely used to solve FJSPs. Based on the best schedules among them, the rule learning with data transformation phase converts them into training data with constructed attributes and generates a dispatching rule with inductive learning. Finally, the rule improvement with discretisation improves dispatching rules with a genetic algorithm by discretising continuous attributes and changing parameters for random forest with the aim of minimising the average total weighted tardiness. We conducted experiments to verify the performance of the proposed approach and the results showed that it outperforms the existing dispatching rules. Moreover, compared with the other decision-tree-based algorithms, the proposed algorithm is effective in terms of extracting scheduling insights from a set of rules.