• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.890-893
• /
• 2010

In wireless sensor networks, each node generally uses a battery because it is hard to replace or charge. For this reason, study for life time prolongation of each node within the limited energy source has become an important issue. So many ways are suggested to minimize the energy consumption for each node, especially energy efficient MAC protocols have been studied actively. T-MAC of contention based MAC protocol is that added the adaptability on fixed duty cycle of S-MAC. T-MAC allocates the fixed timeout before each node goes to sleep mode from active mode. If no data exchanged in a timeout, each node goes to sleep mode. Because of the timeout is always fixed, the absence of data exchange in a timeout will cause unnecessary energy consumption. In this paper, in order to improve the energy efficiency, we propose a MAC protocol based on adaptive timeout that analyze the probability of the timeout, and provides the modified timeout.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.8
• /
• pp.1542-1550
• /
• 2015

Delayed ACK is an algorithm implemented to decrease the number of ACK transmissions by delaying an ACK transmission and by waiting for additional ACK instead of transmitting the ACK immediately. By using Delayed ACK in TCP, the congestion of network and the overhead of handling ACKs can be reduced. Waiting time of Delayed ACK is defined as the Delayed ACK timeout, and it is fixed in Window OS basically. However, the fixed value of Delayed ACK timeout is not suitable for dynamic network circumstance, and it may cause unnecessary delay. This paper proposes a regulating Delayed ACK timeout algorithm to reduce the aforementioned unnecessary delay caused by the lengthy default value of the Delayed ACK timeout. We confirm that TCP transmission performance in dynamic network circumstance can be improved using the proposed algorithm.

• The Korean Journal of Rehabilitation Nursing
• /
• v.18 no.1
• /
• pp.29-37
• /
• 2015

Purpose: This study was conducted to develop effective timeout protocol in coordination with current practice and test its clinical effectiveness in pursuit of safety management for patients undergoing cataract surgery. Methods: A total of subjects were 60 women, 50~65 years old, who visit C ophthalmology clinic in D city. They were assigned to 30 experimental group and 30 control group, respectively. Based on the comprehensive literature review, timeout protocol that was suitable for patients undergoing cataract surgery was developed, and then test its effectiveness by measuring blood pressure, pulse, anxiety and sense of well-being among surgical patients. Results: The timeout protocol was found to reduce blood pressure, pulse, and anxiety and increase well-being among surgical patients. Conclusion: As a results, it is necessary to introduce an effective timeout protocol giving positive responses to surgical patients, hence it should be develop a timeout protocol and explore the effectiveness of the protocol.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2003.11a
• /
• pp.439-442
• /
• 2003

세션 관리 시스템에서 많은 세션에 대한 timeout 처리 시 발생하는 오버헤드를 줄이기 위한 방법으로 기존의 time based timeout 관리 방식이 아닌, 세션 관리 시스템의 성격에 적합한, event based timeout 관리 방법을 제시하고 실험을 통해 확인해 본다.

• Korean Journal of Adult Nursing
• /
• v.20 no.2
• /
• pp.353-363
• /
• 2008

Purpose: This study was conducted to develop a timeout protocol as the process of patients verification in the operating room, and to evaluate its effects. Methods: The timeout protocol was developed based on the experience of practices and the universal protocol of JCAHO 2004. The subjects of this study were 192 surgical members working in the operating room at an university hospital in Daegu, Korea. Results: The timeout protocol was developed in six steps; participants verification, encouragement of compliance, verification of right 3 PSP, agreement of surgical team members, verification of the parties to a patient, patient agreement. The data which have been resulted from the experimental group show significantly higher than those of control group as follows; cognition(t = -6.580, p = .000), contents of performance; progress of anesthesiologist as leader(${\chi}^2$ = 29.029, p = .000), verification of right patient, right site and right procedure(${\chi}^2$ = 40.663, p = .000), participation of surgical team(${\chi}^2$ = 68.412, p = .000), and the number of cases of performance(${\chi}^2$ = 242.900, p = .000). Conclusion: It suggests that medical accidents caused by failures in a preoperative verification process can be prevented if a timeout is conducted active involvement and effective communication among surgical team members for a final verification of the correct patient, procedure, and site.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.5B
• /
• pp.326-333
• /
• 2008

In wireless sensor networks, a sensor node with in-network aggregation adjusts the timeout which is a waiting time to receive messages from child nodes. This paper proposes a novel timeout scheduling scheme for data aggregation in wireless sensor networks, which adaptively configures its timeout according to changing data patterns in order to improve energy efficiency and data accuracy during data aggregation. The proposed scheme decreases the timeout when the temporal difference of collected data(data variation) from children is lower than a pre-defined threshold because there is no occurrence of critical events. Conversely, it increases the timeout when the data variation is higher than the pre-defined threshold in order to fulfill more accurate data aggregation. Extensive simulation reveals that the proposed scheme outperforms the cascading-based scheme in terms of energy consumption and data accuracy.

• Journal of Communications and Networks
• /
• v.6 no.1
• /
• pp.38-45
• /
• 2004

The ABR point-to-multipoint connection is now playing a more important role than before. Many consolidation algorithms have been proposed to solve the consolidation noise problem and the slow transient response problem. But few timeout algorithms are proposed to handle the non-responsive branches for the multicast connections. Chen’s algorithm needs exchanging control messages between switches [9]. Besides, it may mistake a responsive branch as a non-responsive branch because of fast changes in source rates, which causes wrong information in BRM cells and may lead to network congestion and data losses in the responsive branch. We propose a simple timeout algorithm which can handle the non-responsive branches without exchanging message between switches. The timeout value for each switch is computed locally. Simulation results show that the proposed timeout algorithm can efficiently handle the non-responsive branches and utilize the available bandwidth within a small period of time. In addition, our algorithm could handle the situation when the source rates change quickly.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.53 no.12
• /
• pp.813-819
• /
• 2004

This paper infers two patterns of timeout from the characteristics of TCP Reno and confirms the existence of the patterns by conducting actual experiments. All timeouts can be classified into either of these patterns by using the history of RTT value. Based on the observed patterns, the paper proposes two algorithms to improve the performance of TCP Reno. Experimental results show that, when compared with TCP Reno, the proposed algorithms improve the bandwidth utilization by 3 to 12 percent. The paper provides good examples of how timeout-based and delay-based congestion control can efficiently work together.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.12
• /
• pp.933-937
• /
• 2009

This paper proposes a dynamic timeout scheduling for energy efficient and accurate aggregation by analyzing the single hop delay in wireless sensor networks based on IEEE 802.15.4. The proposed scheme dynamically configures the timeout value depending on both the number of nodes sharing a channel and the type of wireless media, with considering the results of delay analysis of the single hop delay. The timeout of proposed scheme is much smaller than the maximum single hop delay which is used as the timeout of traditional data aggregation schemes. Therefore the proposed scheme considerably reduces the energy consumption of idle monitoring for waiting messages. Also, the proposed scheme maintains the data accuracy by guaranteeing the reception ratio required by the sensor network applications. Extensive simulation has revealed that proposed scheme enhances energy consumption by 30% with maintaining data accuracy, as compared with the TAG data aggregation.

• The KIPS Transactions:PartA
• /
• v.11A no.2
• /
• pp.143-148
• /
• 2004

The session management overhead on the network systems like firewalls or intrusion detection systems is getting grown as the session table is glowing. In this paper. we propose the event-based timeout management policy to increase packet processing throughput on network systems by decreasing the system's timeout management overhead that is comparable to the existing time-based timeout management policies. Through some empirical studies using a session management system implemented in this paper we probed that the proposed policy provides better packet processing throughput than the existing policies.