• Journal of Digital Contents Society
• /
• v.16 no.5
• /
• pp.783-793
• /
• 2015

TV display which existed only in house started to show up out of house around us and now it found naturally its place in everywhere like street, bus, subway and elevator. It is called digital signage which showed up through digitalization of sign, that is, sign board and bulletin board. The distinction of digital sign from existing signs is that the latter one should go through physical process like removal after installation every time its contents are changed but the former one can produce its various outputs flexibly once it is installed. Also existing sign may be static image or 2 or 3 pieces of image to express simple motion while digital sign can contain multi media contents luxurious in design and motion. This paper confined the range of contents in digital signage in bus and subway. It needs to analyze characteristics of mass transportation-people of use, consumer by place and time, accommodation environment for consumer etc and arrange planned contents along with time and place. Developments of dedicated contents suitable to those digital signages will harmonize with place and time and promote the realm of digital signage which provides variety of experience to consumer and with which communication is possible and which is distinctive. Furthermore we may expect the birth of smart signage as a new media, in which fun and art are combined.

• Polymer(Korea)
• /
• v.38 no.6
• /
• pp.752-759
• /
• 2014

Crosslinked polyimides (PIs) were synthesized by reacting 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) and 2,2'-bis(trifluoromethyl)benzidine (TFDB) with various ratios of the cross-linkable, end-capping agent cis-1,2,3,6-tetrahydrophthalic anhydride (CDBA) via ring-opening metathesis polymerization. Residual stress behaviors were investigated in-situ during thermal imidization of the crosslinked PI precursors using a thin film stress analyzer (TFSA) by wafer bending method. The thermal properties were investigated via differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermogravimetric analysis (TGA). The optical properties were measured by ultraviolet-visible spectrophotometer (UV-vis) and spectrophotometry. All properties were interpreted with respect to their morphology of crosslinked networks. With increasing the amounts of the end-capping agent, the residual stress decreased from 27.9 to -1.3 MPa, exhibited ultra-low stress and high thermal properties. The minimized residual stress and enhanced thermal properties of the crosslinked PI makes them potential candidates for versatile high-density multi-layer structure applications.

• Journal of the HCI Society of Korea
• /
• v.13 no.3
• /
• pp.43-53
• /
• 2018

Facebook, which has the largest number of users worldwide, has both positive and negative effects on our lives and society. The positive effects include social support from others, relationship building, entertainment, etc. In contrast, Facebook users also experience negative emotions such as tiredness and irritation, resulting in dissatisfaction as well as withdrawal from Facebook. The current study investigates both positive and negative effects of the use of by different demographic characteristics (i.e., age and gender), Facebook usage pattern (i.e., posters vs. lurkers), and Facebook usage time and frequency. The results show that (1) female users (vs. male users) feel higher level of fatigue and display stronger intention to discontinue Facebook. Moreover, (2) posters (vs. lurkers) feel higher level of positive emotions and social support, and stronger intention to continue Facebook. Lastly, (3) heavy users (vs. light users) exhibit higher level of positive emotions and stronger intentions to continue Facebook. This research sheds light on the fact that the characteristics of users affect individuals' intention to discontinue SNS and offers practical implications on the ever-expanding SNS market.

• Convergence Security Journal
• /
• v.2 no.1
• /
• pp.87-97
• /
• 2002

Many firms are utilizing the Internet and various information technologies to effectively manage their business operations with a goal of gaining a competitive advantage in the rapidly changing business environments. Today, the business is characterized as digital economy where information freely flows and business processes are improved with the use of information technologies. Internet technology is playing a key role in transforming the organization and creating new business models. It has become the infrastructure of choice for electronic commerce because it provides process efficiency, cost reduction, and open standards that can easily be adopted by different organizations. Here, the vast amount of data and information slow among the related parties and security issues are very critical matter of research interests by academicians and practitioners. In this research, we address the importance of security framework in managing the data shared among the related parties in the e-business and suggest the security architecture for effectively supporting the needs of e-business in an organization. This research provides valuable contributions both in academics and industry in terms of how security framework and architecture should be set in order to provide the necessary e-business.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.7A
• /
• pp.649-658
• /
• 2006

Recently, Software Development was applied to new-approach methods as a various form : client-server system and web-programing, object-orient concept, distributed development with a network environments. On the other hand, it be concerned about the distributed development technology and increasing of object-oriented methodology. These technology is spread out the software quality and improve of software production, reduction of the software develop working. Futures, we considered about the distributed software development technique with a many workstation. In this paper, we discussed optimal release problem based on a stochastic differential equation model for the distributed Software development environments. In the past, the software reliability applied to quality a rough guess with a software development process and approach by the estimation of reliability for a test progress. But, in this paper, we decided to optimal release times two method: first, SRGM with an error counting model in fault detection phase by NHPP. Second, fault detection is change of continuous random variable by SDE(stochastic differential equation). Here, we decide to optimal release time as a minimum cost form the detected failure data and debugging fault data during the system test phase and operational phase. Especially, we discussed to limitation of reliability considering of total software cost probability distribution.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.10C
• /
• pp.1015-1026
• /
• 2002

As per increasing research interest in the field of collaborative computing in recent year, the importance of security issues on that area is also incrementally growing. Generally, the persistency of collaborative system is facilitated with conventional authentication and cryptography schemes. It is however, hard to meet the access control requirements of distributed collaborative computing environments by means of merely apply the existing access control mechanisms. The distributed collaborative system must consider the network openness, and various type of subjects and objects while, the existing access control schemes consider only some of the access control elements such as identity, rule, and role. However, this may cause the state of security level alteration phenomenon. In order to handle proper access control in collaborative system, various types of access control elements such as identity, role, group, degree of security, degree of integrity, and permission should be taken into account. Futhermore, if we simply define all the necessary access control elements to implement access control algorithm, then collaborative system consequently should consider too many available objects which in consequence, may lead drastic degradation of system performance. In order to improve the state problems, we propose a novel access control framework that is suitable for the distributed collaborative computing environments. The proposed scheme defines several different types of object elements for the accessed objects and subjects, and use them to implement access control which allows us to guarantee more solid access control. Futhermore, the objects are distinguished by three categories based on the characteristics of the object elements, and the proposed algorithm is implemented by the classified objects which lead to improve the systems' performance. Also, the proposed method can support scalability compared to the conventional one. Our simulation study shows that the performance results are almost similar to the two cases; one for the collaborative system has the proposed access control scheme, and the other for it has not.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.1
• /
• pp.152-164
• /
• 2015

A rapid development of semiconductors, sensors and mobile network technologies has enable that the embedded device includes high sensitivity sensors, wireless communication modules and a video processing module for vehicular environment, and many researchers have been actively studying the smart car technology combined on the high performance embedded devices. The vehicle is increased as the development of society, and the risk of accidents is increasing gradually. Thus, the advanced driver assistance system providing the vehicular status and the surrounding environment of the vehicle to the driver using various sensor data is actively studied. In this paper, we design and implement the smart vehicular camera device providing the V2X communication and gathering environment information. And we studied the method to create the metadata from a received video data and sensor data using video analysis algorithm. In addition, we invent S-ROI, D-ROI methods that set a region of interest in a video frame to improve calculation performance. We performed the performance evaluation for two ROI methods. As the result, we confirmed the video processing speed that S-ROI is 3.0 times and D-ROI is 4.8 times better than a full frame analysis.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.1
• /
• pp.96-107
• /
• 2015

VANET technologies provide real-time traffic information for mitigating traffic jam and preventing traffic accidents, as well as in-vehicle infotainment service through Telematics/Intelligent Transportation System (ITS). Due to the rapid increasement of various requirements, the vehicle communication with a limited resource and the fixed frame architecture of the conventional techniques is limited to provide an efficient communication service. Therefore, a new flexible operation depending on the surrounding situation information is required that needs an adaptive design of the network architecture and protocol for efficiently predicting, distributing and sharing the context-aware information. In this paper, Vehicle-to-Infrastructure (V2I) based on communication between vehicle and a Road Side Units (RSU) and Vehicle-to-Vehicle (V2V) based on communication between vehicles are effectively combined in a new MAC architecture and V2I and V2V vehicles collaborate in management. As a result, many vehicles and RSU can use more efficiently the resource and send data rapidly. The simulation results show that the proposed method can achieve high resource utilization in accordance. Also we can find out the optimal transmission relay time and 2nd relay vehicle selection probability value to spread out V2V/V2I collaborative schedule message rapidly.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.4B
• /
• pp.332-345
• /
• 2011

As weapon systems are evolving into more advanced and complex ones, the role of the software is becoming heavily significant in their developments. Particularly in the war field of today as represented by the network centric warfare(NCW), the reliability of weapon systems is definitely crucial. In this context, it is inevitable to develop software reliably enough to make the weapon systems operate robustly in the combat field. The reliability engineering activities performed to develop software in the domestic area seem to be limited to the software reliability estimations for some projects. To ensure that the target reliability of software be maintained through the system's development period, a more systematic approach to performing software reliability engineering activities are necessary from the beginning of the development period. In this paper, we consider the software reliability in terms of the development of a weapon system as a whole. Thus, from the systems engineering point of view, we analyze the models and methods that are related to software reliability and a variety of associated activities. As a result, a process is developed, which can be called the software reliability engineering process for weapon systems (SREP-WS), The developed SREP-WS can be used in the development of a weapon system to meet a target reliability throughout its life-cycle. Based on the SREP-WS, the software reliability could also be managed quantitatively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.12A
• /
• pp.950-958
• /
• 2011

This paper focuses in the implementation of mesh router supporting multi-path routing based on IEEE 802.11s. In HWMP of IEEE 802.11s, the single path routing just was defined. So, in this work, we implemented not only the single path routing defined in IEEE 802.11s, but also a multipath routing based on AOMDV which extended the standard. A multi-channel multi-interface technology that can transmit and receive simultaneously and lower bandwidth reduction caused by interferences than a single-channel single-interface was implemented in our mesh router. We also developed an outdoor test bed with the mesh routers. The bandwidth of the mesh router and a real-time video streaming service were verified using the test bed. And, the single path and multipath routing algorithms are also compared. In this test bed, The average TCP bandwidth was 23.77 Mbps and the latency was 2.4 ms in five hops. The test bed could service real-time streaming with an average jitter of 0.547 ms in five hops. The mesh router that used the multipath routing path reduced the path recovery time by 12.73% on average.