• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.778-790
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• 2004

In this paper, we propose the functional models of optical burst switching (OBS) routers to apply GMPLS (Generalized Multiprotocol Label Switching) to optical networks based on OBS. In addition, we introduce a connection admission control (CAC) algorithms which are operated in this models and can accommodate the required QoS. Firstly, the characteristics of current GMPLS and OBS for the optical Internet are basically considered. With this consideration, the models are proposed to accept OBS features which include the recognition of data bounda η with control information and the statistical multiplexing in terms of bursts. Secondly, we use an offset time decision (OTD) algorithm on behalf of controlling the connection admission with taking QoS parameters such as burst loss rate(BLR) and service-differentiation ratio(SDR) into consideration. The proposed CAC algorithms use the offered load of LSP (Label Switched Path), wavelength information, and QoS parame ‘ ers as inputs of OTD algorithm. A call setup request will be accepted when the offset time decided by OTD algorithm is reasonable for guaranteeing its requested QoS. Simulation is used for performance evaluation Results show the proposed schemes can guarantee the required QoS and those are better than the previous one in terms of channel utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.7B
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• pp.489-498
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• 2012

Recently, as the interest in Green IT is exponentially increased, EPON with sleep mode has been studied to reduce energy consumption in access network. In oder to guarantee cyclic sleep for ONU(Optical Network Units), EPON with sleep mode transmits upstream and downstream data at the same time. However, since conventional algorithms for sleep mode in EPON allocate bandwidth to each ONU according to upstream bandwidth request, the QoS of downstream data is not guaranteed when the offered load of OLT is larger than that of ONU. In this paper, we propose a bandwidth allocation algorithm for improving QoS in EPON with sleep mode. The proposed algorithm compares its size with an upstream request of ONU when a downstream buffer in the OLT exceeds a QoS threshold. And then it allocates selectively a bandwidth that satisfies the required QoS between the bandwidth request of ONU and OLT. Therefore, the proposed algorithm can save energy through cyclic sleep of ONUs while guaranteeing the QoS of up/downstream data. In order to evaluate the proposed algorithm, we perform simulation in terms of total sleep time of ONUs, queueing delay between OLT and ONU, and the utilization of allocated bandwidth at OLT through OPNET.

• Food Science and Preservation
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• v.15 no.5
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• pp.622-629
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• 2008

This study investigated changes in quality characteristics of wrap- and vacuum-packaged peeled lotus roots treated with strong acidic electrolyzed acid water (SAEW pH 2.58, ORP 1,128 mV, HClO 105.0 ppm) or low alkaline electrolyzed water (LAEW pH 8.56, ORP 660 mV, HClO 73.8 ppm) as immersion liquids prior to packaging and storage at 5C. Immersion of peeled lotus roots in SAEW and LAEW reduced initial microbial load by about 1 log compared to treatment with tap water (TW). Hardness differences on storage were observed. However, reduction in PPO activity by electrolyzed water was not reproducible. Changes in Hunter's color value and the color difference value ($\Delta$) of peeled lotus roots immersed in 0.5% (w/v) sodium metabisulfite (SMS) and electrolyzed water were smaller than those of roots treated with TW prior to storage. Sensory characteristics measured during storage were best-preserved in lotus roots previously immersed in 0.5% (w/v) SMS or electrolyzed water, compared to TW. Immersionin electrolyzed water and vacuum packaging preserves the quality of peeled lotus roots in terms of microbial, visual, and sensory aspects, at levels comparable to those offered by storage after treatment with 0.5% (w/v) SMS.