• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.37 no.1
• /
• pp.32-43
• /
• 2000

In this paper, we investigate the existing medium access control (MAC) protocols to integrate the voice and data services in packet-based CDMA networks and furthermore, propose a new approach to circumvent the operational limits inherent in them. We propose the $P^2R$-CDMA (Prioritized Packet Reservation Code Division Multiple Access) protocol for the uplink in the synchronous multi-code CDMA system, which employs the centralized frame-based slot reservation along with the dynamic slot assignment in the base station using the QoS-oriented dynamic priority of individual terminal. The simulation results show that, as compared with the existing scheme based on the adaptive permission probability control (APC), the proposed approach can significantly improve the system capacity while guaranteeing the real-time requirement of voice service.

• Journal of the Korea Society for Simulation
• /
• v.17 no.3
• /
• pp.85-94
• /
• 2008

Automated Guided Vehicles (AGVs) are important equipment in automated container terminals. To utilize AGVs for transporting containers from a position to another, the deadlock is a serious problem that must be solved before they are deployed to real operations. This study assumes that traveling area for AGVs are divided into a large number of grid-blocks and, as a method of traffic control, grid-blocks are reserved in advance during the travel of AGVs. The purposes of the reservation are to make the room between AGVs and to prevent deadlocks. Because the size of an AGV is much larger than the size of a grid-block on guide paths, this study assumes an AGV may occupy more than one grid-block at the same time. This study suggests a method for constructing a table of reservation schedules by using a simulation. A sensitivity analysis was conducted to evaluate the performance of the reservation method in this study.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.2
• /
• pp.250-260
• /
• 1993

Packet Reservation Multiple Access(PRMA) protocol provides a very efficient mechanism for many number of voice and data terminals with bursty traffic characteristics to share efficiently a common transmission channel. This protocol, however, cannot operate in high load conditions. That is, there occurs a instability problem, since the reservation channel is allowed to shrink to zero. In this paper, a more stable PRMA protocol which can avoid such problems and integrates voice and data traffic efficiently is proposed. Also, the performance of the proposed protocol is analyzed by a computer simulation. According to the simulation results, it can be shown that the proposed protocol provides a more efficient mechanism for voice/data integration and ensures a more stable operation than conventional PRMA protocol in high load conditions.

• Journal of the Korea Computer Industry Society
• /
• v.8 no.2
• /
• pp.89-96
• /
• 2007

The object-based reservation scheduling techniques are to solve complex scheduling problems using constraint satisfaction problems and object-oriented concepts. We have tried to apply the object-based reservation scheduling techniques to the flight operation scheduling problems. For crew's satisfaction, we have considered the total crew's preferences board in the flight operation scheduling. To consider the over all satisfaction, the events of every object are alloted to the board along its priority. Constraints to reservation scheduling are classified to global and local. The definition of board and information of every event are global constraints and the preferences to object's board slots are local constraints. Actually, we have made an experiment on flight operation scheduling in order to raise crew's satisfaction.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.7A
• /
• pp.766-774
• /
• 2004

The future mobile communication system can support not only voice but also multimedia applications such as data, image and video. It requires greater resources than the voice-oriented mobile system. Efficient resource reservation and hand-over schemes are necessary to maintain the same QoS of transmitted multimedia traffic because the QoS may be defected by some delay and information loss during hand-over. This paper proposes a resource reservation scheme to accommodate multimedia traffics in mobile multimedia networks. In our scheme the position of mobile is estimated in two steps, that is, sector estimation and zone estimation. With this position information, the moving direction is determined. According to simulation results, our scheme provides a better performance than conventional methods.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.2
• /
• pp.257-262
• /
• 2001

A new WDM-based protocol for scheduling a variable-length message is proposed in this paper Two control channels, reservation slot and control slot, are used to coordinate transmission and diminish the collisions of packet to minimize the across delay. When an idle control slot is available, control packet is transmitted on that slot and message is transferred. And the node continues to transmit its control packet through the corresponding slot every cycle, until the message is completely transmitted. If any control slot is not available, the node schedules the transmission time of message in earliest available time using reservation slots. The proposed scheduling algorithm shows better performance and lower access delay.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.7
• /
• pp.696-708
• /
• 1992

In this study, we have several objectives. First, In spite of a fixed bandwidth waste of reservation channel, we maximize the efficiency of transmission channel by the multiple access algorithm that performs channel reservation and data transmission independently, eliminating the frame structure of transmission channel and reserving it by the slot unit . Second, In order to improve the entire system performance, we accommodate the variation of traffic at each earth station more effectively, and accomplish the stable delay characteristics and the equlity of service #or users. For this purpose, we design the satellite channel that consists of reservation channel and transmission channel which are logically separate and operate Independently. We also design a demand assignment multiple access algorithm based on the satellite channel structure.

• KIPS Transactions on Computer and Communication Systems
• /
• v.2 no.8
• /
• pp.343-348
• /
• 2013

We proposes a power-aware fixed-priority real-time scheduling algorithm for multimedia service, called static voltage scaling algorithm with multi-granularity resource reservation (STATIC-MULTIRSV). The multi-granularity resource reservation was introduced to deliver higher system utilization and better temporal isolation than the traditional approaches in [2]. Based on this, our STATIC-MULTIRSV is designed to reduce the power consumptions while guaranteeing that all I-frames of each video stream meet their deadlines. We implemented the proposed algorithm on top of ChronOS Real-time Linux [6]. We experimentally compared STATIC-MULTIRSV with other existing methods which showed that STATIC-MULTIRSV reduce power consumption by maximum 15% compared to its experimental counterparts.

• Journal of Internet Computing and Services
• /
• v.4 no.5
• /
• pp.61-68
• /
• 2003

In this paper, we propose a wireless MAC protocol named APRMA, which is capable of supporting the ABR type data service and Maximizing channel utilization. Data terminals with random data packets are not provided slot reservation with PRMA protocol. That is, slot reservation is applicable to the time constraint voice packet exclusively. But the reservation scheme have to be performed for loss sensitive data packet, and contended their quality of service, Therefore, in wireless MAC, reservation technique has to be used for both voice and data services. So the terminal which wants to request for ABR type service, is allocated a minimum bandwidth from system for the first time, If the system have some extra available bandwidth, ABR terminals would acquire additional bandwidth slot by slot, As a result, APRMA protocol can support the data service with loss sensitivity and maintain their channel utilization high.

• Journal of English Language & Literature
• /
• v.59 no.4
• /
• pp.569-592
• /
• 2013

In Reservation Blues, Sherman Alexie examines how Indians can survive successfully in contemporary America, overcoming the tragic history of colonialists' violence and the resultant traumata. For Alexie, both reassembling the parts of the colonialist history through remembrance and testifying its unjustness play important roles not only in the decolonization process which probes the remnants and the negative effects of the colonialism deeply rooted in the lives of Indians but in the procedure of healing the political, cultural, and religious traumata. However, it should be noted that the ultimate aim of Alexie's decolonization does not lie in erasing every trace of the colonialism but in transforming its legacy into a story of survivance. The recovery of the tribal voices and the preservation of Indian traditions, blood, and cultures are essential in the survivance of Indians. Yet, Alexie's tribalism should not be viewed as an exclusive one. He knows well that it is neither possible nor desirable to maintain an exclusive tribalism based on blind adherence to a mythic or "pure" past. Exclusive tribalism is a cause for alarm in the contemporary world, a dynamic place where diverse cultures consistently change through collision, exchange, and negotiation. In Reservation Blues, Alexie stresses a spiritual and cultural flexibility that makes the cultural interpenetration possible as a key element of the meaningful survivance of contemporary American Indians.