• KIPS Transactions on Computer and Communication Systems
• /
• v.6 no.7
• /
• pp.297-306
• /
• 2017

Citizens want more accurate forecast information using Bus Information System. However, most bus information systems that use an average based short-term prediction algorithm include many errors because they do not consider the effects of the traffic flow, signal period, and halting time. In this paper, we try to improve the precision of forecast information by analyzing the influencing factors of the error, thereby making the convenience of the citizens. We analyzed the influence factors of the error using BIS data. It is shown in the analyzed data that the effects of the time characteristics and geographical conditions are mixed, and that effects on halting time and passes speed is different. Therefore, the halt time is constructed using Generalized Additive Model with explanatory variable such as hour, GPS coordinate and number of routes, and we used Hidden Markov Model to construct a pattern considering the influence of traffic flow on the unit section. As a result of the pattern construction, accurate real-time forecasting and long-term prediction of route travel time were possible. Finally, it is shown that this model is suitable for travel time prediction through statistical test between observed data and predicted data. As a result of this paper, we can provide more precise forecast information to the citizens, and we think that long-term forecasting can play an important role in decision making such as route scheduling.

• Journal of Construction Engineering and Project Management
• /
• v.7 no.1
• /
• pp.13-25
• /
• 2017

Construction projects have been observed to have problems of project delays and disruptions and the South African construction industry is not an exception. This research identified causes and effects of project delay and disruption through a desktop study. Subsequently, a questionnaire was designed and used to conduct a survey to obtain the views of the three main construction project participants - clients, consultants, and contractors. The questionnaire contains 48 causes and 13 effects of project delay and disruption identified from the desktop study. This research identified sixteen most important causes of project delay and disruption and five most important effects of delay and disruption. Sixteen most important causes were: (1) strikes, (2) rework due to errors during construction, (3) shortage of materials in market, (4) suspension of work by the client, (5) poor communication between the parties, (6) ineffective planning and scheduling of project, (7) delays in issuing working drawings, (8) mistakes and discrepancies in design documents, (9) shortage of labours and equipment, (10) delay in decision making process by the client, (11) unforeseen ground conditions, (12) unclear and inadequate details in drawing, (13) inadequate contractor's experience, (14) delay in approving changes in the scope of works, (15) delay in material delivery and (16) unacceptable quality of materials. The five major effects include: (1) create stress on contractors, (2) cost overrun, (3) time overrun, (4) poor quality of work due to rush, and (5) disputes. Furthermore, the result of this research was compared with the result of previous studies conducted in other regions of Africa in terms of causes and effects of project delay and disruption. The research concludes that numerous causes and effects of delay and disruption are limited to South African construction projects based on the comparison. The causes limited to South African construction projects include: (1) strikes, (2) suspension of work by the client (3) mistakes and discrepancies in design documents (4) delay in approving changes in the scope of works and (5) unacceptable quality of materials, while the two major effects limited to South African construction projects includes: (1) create stress on contractors and (2) poor quality of work. In conclusion, some recommendations were made in order to minimise the causes of delay and disruption identified.

• The KIPS Transactions:PartD
• /
• v.9D no.2
• /
• pp.235-242
• /
• 2002

We propose an advanced transaction scheduling protocol for concurrency control of multilevel secure databases in wireless mobile network environment. Wireless communication is characterized by frequent spurious disconnections. So short-lived transaction must quickly access database without any delay by long-lived one. We adapted two-phase locking protocol, namely traditional syntax-oriented serializability notions, to multilevel secure databases in wireless mobile network environment. Altruistic locking, as an advanced protocol, has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of a1truism has also been deployed for extended a1truistic locking. This is in a way that scope of data to he early released is enlarged to include even data initially not intended to be donated. Our protocol is based on extended altruistic locking, but a new method, namely bi-directional donation locking for multilevel secure databases (MLBiDL), is additionally used in order to satisfy security requirements and concurrency. We showed the Simulation experiments that MLBiDL outperforms the other locking protocols in terms of the degree of throughput and average waiting time.

• Journal of IKEEE
• /
• v.11 no.4
• /
• pp.348-357
• /
• 2007

Due to the improved performance and cost of personal mobile devices and rapid progress of wireless communication technology, the number of users who utilize these devices is increasing. This trend requires various types of services be available to users. So far, there have been many solutions provided for the shortest path problem. But, technologies which can offer various recommendation services to user depending on user’s current location are focused on Euclidean spaces rather than road network. Thus, in this paper, we extend the previous work to satisfy this requirement on road network database. Our proposed scheme requires pre-computation for the efficient query processing. In the preprocessing step, we first partition the input road network into a fixed number of Voronoi polygons and then pre-compute routing information for each polygon. In the meantime, we select the number of Voronoi polygons in proposition to the scale of road network. Through this selection, the required size of pre-computation is linearly increasing to the size of road network. Using this pre-computated information, we can process queries more quickly. Through experiments, we have shown that our proposed scheme can achieve excellent performance in terms of scheduling time and the number of visited nodes.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.7
• /
• pp.370-379
• /
• 2006

Computational grid provides the environment which integrates v 따 ious computing resources. Grid environment is more complex and various than traditional computing environment, and consists of various resources where various software packages are installed in different platforms. For more efficient usage of computational grid, therefore, some kind of integration is required to manage grid resources more effectively. In this paper, a global scheduler is suggested, which integrates grid resources at meta level with applying various scheduling policies. The global scheduler consists of a mechanical part and three policies. The mechanical part mainly search user queues and resource queues to select appropriate job and computing resource. An algorithm for the mechanical part is defined and optimized. Three policies are user selecting policy, resource selecting policy, and executing policy. These can be defined newly and replaced with new one freely while operation of computational grid is temporarily holding. User selecting policy, for example, can be defined to select a certain user with higher priority than other users, resource selecting policy is for selecting the computing resource which is matched well with user's requirements, and executing policy is to overcome communication overheads on grid middleware. Finally, various algorithms for user selecting policy are defined only in terms of user fairness, and their performances are compared.

• The KIPS Transactions:PartC
• /
• v.15C no.4
• /
• pp.281-288
• /
• 2008

Recently, the advance of multimedia hardware has fostered the development of wireless multimedia sensor network which is able to ubiquitously obtain multimedia content such as image or audio from the environment. The multimedia data which has several characteristics such as large size and correlation between the data requires reliability in transmission. However, the existing solution which take the focus on the efficiency of network mainly, is not appropriate to transmit the multimedia data. In the paper, we proposes a reliable asynchronous image transfer protocol, RAIT. RAIT applies double sliding window method in node-to-node image tansfer to prevent the packet loss caused by network congestion. The double sliding window consists of one sliding window for the receiving queue, which is used for prevention of packet loss caused by communication failure between nodes and the other sliding window for the sending queue which prevents the packet loss caused by network congestion. the routing node prevents the packet loss and guarantees the fairness between the nodes by scheduling the packets based on the image non-preemptively. The RAIT implements the double sliding window method by cross layer design between RAIT layer, routing layer, and queue layer. The experiment shows that RAIT guarantees the reliability of image transmission compared with the existing protocol.

• Journal of KIISE:Information Networking
• /
• v.36 no.4
• /
• pp.339-350
• /
• 2009

In wireless sensor networks, the limited battery resources of sensor nodes have a direct impact on network lifetime. To reduce unnecessary power consumption, it is often the case that only a minimum number of sensor nodes operate in active mode while the others are kept in sleep mode. In such a case, however, the network service can be easily unreliable if any active node is unable to perform its sensing or communication function because of an unexpected failure. Thus, for achieving reliable sensing, it is important to maintain the sensing level even when some sensor nodes fail. In this paper, we propose a new fault-tolerance scheme, called FCP(Fault-tolerant Coverage Preserving), that gives an efficient way to handle the degradation of the sensing level caused by sensor node failures. In the proposed FCP scheme, a set of backup nodes are pre-designated for each active node to be used to replace the active node in case of its failure. Experimental results show that the FCP scheme provides enhanced performance with reduced overhead in terms of sensing coverage preserving, the number of backup nodes and the amount of control messages. On the average, the percentage of coverage preserving is improved by 87.2% while the additional number of backup nodes and the additional amount of control messages are reduced by 57.6% and 99.5%, respectively, compared with previous fault-tolerance schemes.

• Journal of Industrial Convergence
• /
• v.16 no.1
• /
• pp.21-26
• /
• 2018

The Seaborne Trade Volume accounts for 97% of the total. This means that the port operation management system can improve port efficiency, reducing operating costs, and the manager who manages all operations at the port needs to check and respond quickly when delays of work and equipment support is needed. Based on the real-time location information confirmation of yard automation equipment used the existing system GPS, the real-time location information confirmation system is a GPS system of the tablet, rather than a port operation system that monitors location information for the entered information, depending on the completion of the task or the start of the task. Network configurations also reduce container processing delays by using commercial LTE services that do not have shading due to containers in the yard also reduce container processing delays. Trough introduction of smart devices using Android or IOS and container processing scheduling utilizing artificial intelligence, we will build a minimum delay system with Smart Device usage of container processing applications and optimization of container processing schedule. The adoption of smart devices and the minimization of container processing delays utilizing artificial intelligence are expected to improve the quality of port services by confirming the processing containers in real time to consumers who are container information demanders.

• Journal of Korea Entertainment Industry Association
• /
• v.15 no.8
• /
• pp.107-116
• /
• 2021

In recent years, the research on audience satisfaction after watching programs has been carried out in various fields. However, there is no precedent for the study of simply analyzing the influencing factors of audience satisfaction with the newly established CCTV-9 channel. For CCTV-9, how to explore the strategy of industrial development based on the needs of the audience in the era of big data is a very important part. This article exploratively focuses on the influencing factors related to CCTV-9 audience satisfaction. Using questionnaires, 101 samples of the satisfaction with the channel of men and women of different ages, education backgrounds, majors, and incomes were collected to test, and 9 hypotheses were tentatively proposed as relevant influencing factors of channel satisfaction. Through empirical analysis, this research searches for the determinants. The reliability and validity of the measurement were properly analyzed, and all hypotheses were statistically tested. The empirical results show that: subject matter, program format, program scheduling, program broadcast time, channel advertising, simulcast series of documentaries, diversified communication platforms, brand image packaging and audience satisfaction are significantly positively correlated.

• Korean journal of communication and information
• /
• v.35
• /
• pp.250-291
• /
• 2006

This study examines the regulatory issues and introduction problems of TV-betting data broadcasts in Korea by in-depth interview with a panel group. TV-betting data broadcast services of card games and horse racing games are widely in use in Europe and other parts of the world. In order to carry out the study, a demo program of TV-betting data broadcast in the OCAP(OpenCableTM Application Platform Specification) system environment, which is the data broadcasting standard for digital cable broadcasts in Korea was exposed to the panel group and then they were interviewed after watching and using the program. The results could be summarized as below. First of all, while TV-betting data broadcasts have many elements of entertainment, the respondents thought that it would be difficult to introduce TV-betting in data broadcasts as in overseas countries largely due to social factors. In addition, in order to introduce TV-betting data broadcasts, they suggested that excessive speculativeness must be suppressed through a series of regulatory system devices, such as by guaranteeing credibility of the media based on safe security systems for transactions, scheduling programs with effective time constraints to prevent the games from running too frequently, limiting the betting values, and by prohibiting access to games through set-top boxes of other data broadcast subscribers. The general consensus was that TV-betting could be considered for gradual introduction within the governmental laws and regulations that would minimize its ill effects. Therefore, the government should formulate long-term regulations and policies for data broadcasts. Once the groundwork is laid for safe introduction of TV-betting on data broadcasts within the boundary of laws and regulations, interactive TV games are expected to be introduced in Korea not only for added functionality of entertainment but also for far-ranging development of data broadcast and new media industries.