• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1C
• /
• pp.21-35
• /
• 2002

Nowadays, in accordance with increasing expectations of multimedia stream service on the internet, a lot of distributed applications are being required and developed. But the models of the existing systems have the problems that cannot support the extensibility and the reusability, when the QoS relating functions are being developed as an integrated modules which are suited on the centralized controlled specific-purpose application services. To cope with these problems, it is suggested in this paper to a distributed QoS management system on CORBA, an object-oriented middleware compliance. This systems we suggested can provides not only for efficient control of resources, various service QoS, and QoS control functions as the existing functions, but also QoS control real-time negotiation and dynamic adaptation in addition. This system consists of QoS Control Management Module(QoS CMM) in client side and QoS Management Module(QoS MM) in server side, respectively. These distributed modules are interfacing with each other via CORBA on different systems for distributed QoS management while serving distributed streaming applications. In phase of design of our system, we use UML(Unified Modeling Language) for designing each component in modules, their method calls and various detailed functions for controlling QoS of stream services. For implementation of our system, we used OrbixWeb 3.1c following CORBA specification on Solaris 2.5/2.7, Java language, Java Media Framework API 2.0 beta2, Mini-SQL 1.0.16 and the multimedia equipments, such as SunVideoPlus/Sun Video capture board and Sun Camera. Finally, we showed a numerical data controlled by real-time negotiation and adaptation procedures based on QoS map information to GUIs on client and server dynamically, while our distributed QoS management system is executing a given streaming service.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.2
• /
• pp.122-125
• /
• 1999

The water quality of the Keum river was surveyed at 4 sites from April to September in 1995 and 1997. Average values of inorganic contents analyzed in 1997 were pH 7.2, EC 0.18dS/m, $NH_4-N$ 0.60mg/l, $K^+$ 4.12mg/l, $Ca^{2+}$ 12.12 mg/l, $Mg^{2+}$ 2.75mg/l, $Na^+$ 15.1mg/l, $NO_3-N$ 1.97mg/l, $PO_4^{3-}$ 0.15mg/l, $PO_4^-$ 18.9mg/l, $Cl^-$ 21.8mg/l, Fe 0.22mg/l, COD 19.7mg/l. On the basis of these values, it was suitable for the irrigation source. Water pH of the Keum river ranged from 6.7 to 8.0. EC of the Daecheong-dam was maintained below 0.13dS/m, but those of the middle and lower stream were ranged from 0.13dS/m to 0.32dS/m. Monthly average values of all the ration contents were the highest in April and were decreased thereafter. And it was slightly increased in September. However $NO_3-N$, $SO_4^{2-}$ contents were higher in June than any other months. All the inorganic contents were the highest at Taepyeong-ri, Yeongi-gun due to sewage water and livestock wastes. The inorganic contents were negatively correlated with precipitation, generally.

• Journal of Korea Multimedia Society
• /
• v.9 no.7
• /
• pp.904-913
• /
• 2006

The QoS(Quality of Service) of VoD(Video on Demand) systems can be improved by reducing the faults that the stream service request from clients is rejected by the VoD server or lost during the service. This paper proposes a model of Dynamic Workload Balancer that can adjust the workload dynamically through the periodical monitoring of the VoD system, and so increase the throughput. The proposed model runs independently from the VoD system by adopting the agent concept. The model comprises the agency part interfacing the VoD system and the intelligence part reasoning or teaming the facts required for the adjustment of workload. An experiment of implementing a simulator was conducted to see whether or not application of the proposed model to VoD system is effective. As a result of the experiment, it was found that the throughput was relatively increased when the proposed model was applied compared to existing means.

• The KIPS Transactions:PartC
• /
• v.15C no.6
• /
• pp.547-556
• /
• 2008

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose a network adaptive prefetching technique, NAP, for guarantee of constant QoS. The NAP prefetches frames by increasing the frame transmission rate while the available network bandwidth is high. The NAP uses the prefetched frames to guarantee the QoS while the available network bandwidth is low. The experiment result shows that the proposed NAP could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.19-24
• /
• 2007

Due to the decreasing of Korean Construction market situation, recently a lot of medium & small size contractors, engineering firms and consulting firms are extending their business area to overseas market. To compare with 80${\sim}$90's situation at that time only Contractor provide service to overseas but in recent, there are number of Design, CM/PM and other consulting services which provide service to overseas. With this figures, the number of nation also increased from middle east and South east asian area to central asia and african nations and among them Kazakhstan has became as new market for the construction industry based on it oil money and up stream of real estimate market. Based on this fact, we will explain one of our recent project case for PM service in Almaty, Kazakhstan to show others who have interest to do business in their.

• Journal of Broadcast Engineering
• /
• v.23 no.2
• /
• pp.316-319
• /
• 2018

When a terrestrial UHD broadcasting service and a mobile HD broadcasting service are provided using the PLP function provided by ATSC 3.0 and domestic UHD broadcasting standard, a small amount of data may be additionally transmitted to further provide high quality UHD-3D broadcasting service. The left and right images of the stereoscopic image are input, one view image is encoded by the SHVC method, and the other view images are encoded by the SHVC method of the two-view cross-referencing method. However, since the base layers (BL) of the two encoders are mutually common, the two encoders correspond to encoders that generate one BL stream and two enhancement layer (EL) streams. The average encoding efficiency is 16% more efficient compared to the third independent HEVC encoding for the UHD-3D broadcast service. The proposed scheme reduces the fluctuation of PSNR per image frame and increases the image quality of minimum PSNR frame by 0.6dB.

• Journal of Satellite, Information and Communications
• /
• v.9 no.4
• /
• pp.38-41
• /
• 2014

Due to the diversity of device performances and the possibility of providing multimedia service through many networks, media consumption environment has been changed in various ways. In recent, mobile services and broadcasting services started to provided through IP network. According to this flow changes, there was great demand for various multimedia services through heterogenous networks. To solve this problem, MMT was suggested as a standard of multimedia transport which replaces MPEG-2 TS(Transport Stream) which is used for HD(High Definition) transport. MMT can be provided various broadcasting based on IP through terrestrial, satellite, cable broadcasting networks, and also deliver multimedia through many networks at the same time. MMT was risen as a method of servicing UHD broadcasting. In this paper, we present an implementation of service architecture for hierarchical UHD broadcasting over heterogenous networks using MMT.

• The KIPS Transactions:PartA
• /
• v.16A no.5
• /
• pp.327-338
• /
• 2009

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose a network adaptive prefetching technique, PAP, for guarantee of constant QoS. The PAP prefetches frames by increasing the frame transmission rate while the available network bandwidth is high. The PAP uses the prefetched frames to guarantee the QoS while the available network bandwidth is low and increases the playout interval to prevent buffer underflow. The experiment result shows that the proposed PAP could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• Journal of Korea Multimedia Society
• /
• v.15 no.12
• /
• pp.1464-1474
• /
• 2012

In this paper, we propose a QoS (Quality of Service)-aware and cooperative resource reservation scheme using cross-layer link adaptation for wireless high definition video transmission through UWB (Ultra Wide Band) network with D-MAC (Distributed Medium Access Control). A wireless high definition video transmission system usually requires stable high throughput even without line-of-sight, e.g., a destination device in another room separated by a wall. Since the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme causes lots of DRP resource reservation conflicts due to failure of beacon detection in wireless channel environment, overall performances of the WiMedia D-MAC can be deteriorated. And the current WiMedia MAC standard has not considered QoS provisioning even though QoS parameters such as a range of service rates are provided to each traffic stream. Therefore, we propose Relay DRP protocol with QoS-based relay node selection criterion, which makes a relay path to avoid DRP resource reservation conflicts and guarantee QoS more stably through cross-layer link adaptation of cooperative relay transmission scheme and is compliant with the current WiMedia D-MAC protocol. Simulation results demonstrate performance improvements of the proposed method for throughput and QoS provisioning.

• Hwankyungkyoyuk
• /
• v.24 no.2
• /
• pp.1-20
• /
• 2011

The purpose of this research is to apply and evaluate the Water Environmental Education Program Using Streams(WEES) to pre-service teachers. WEES is developed to help the teachers increase their professionalism of incorporating a local environment into their inquiry teaching. The subjects of the study include the juniors of the Environmental Education Major at the Korea National University of Education. For the purpose this study, educational criticism about WEES was performed. The subject students were observed throughout the program application, after which a survey and in-depth interviews were carried out. As a result, the implementation elements and content organization of the WEES were found to be implemented in the application process in a satisfying level. In the content organization of the program, the preliminary preparation, visual assessment, and inquiry planning were organically connected with each other for inquiry purposes. The Intrinsic value of environmental education was also demonstrated in the implementation elements and content organization. Overall, the stream turned out to have a great value of environmental education and a potential as a place and material for environmental education. The great significance of the study can be found in that WEES took into account not only the characteristics of the ENVISION based on the watershed concept, but also the situations of Korea's environmental education and exploration from the perspective of environmental studies.