• Journal of Communications and Networks
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• v.13 no.4
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• pp.393-399
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• 2011

We evaluate the link-level performance of cooperative multi-hop relaying networks with an maximum distance separable (MDS) code. The effect of the code on the link-level performance at the destination is investigated in terms of the outage probability and the spectral efficiency. Assuming a simple topology, we construct an absorbing Markov chain. Numerical results indicate that significant improvement can be achieved by incorporating an MDS code. MDS codes successfully facilitate recovery of the message block at a relaying node due to powerful error-correcting capability, so that it can reduce the outage probability. Furthermore, we evaluate the average number of hops where the message block can be delivered.

• KSBB Journal
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• v.17 no.1
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• pp.68-72
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• 2002

Supercritical Carbon Dioxide was evaluated and optimized for the enrichment and fractionation of the essential oil and the bitter principles of hops, both of which contribute to the flavor of beer, Selected conditions of extraction(pressure, temperature and co-solvent) influenced the composition, the olfactory results and the colour of the extract. Optimal extraction conditions were 30 min, 1800 psia and $ >45^{\circ}C $ with co-solvent. Under these conditions, yield was 65% from brewer's yeast. The bittering substances from brewer's yeasts almost were removed.

• ETRI Journal
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• v.28 no.3
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• pp.375-378
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• 2006

This letter presents a pairwise key establishment scheme that is robust against the compromise of nodes in mobile ad hoc networks. Each node establishes local keys with its neighbor nodes that are at most three hops away at network boot-up time. When any two nodes establish a pairwise key, they receive the secret information from the nodes on the route between them, and construct the pairwise key using the secret information. Here, the local keys are utilized by the nodes on the route to send the secret information securely. The simulation results have proven that the proposed scheme provides better security than the key pre-distribution-based scheme.

• ETRI Journal
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• v.39 no.5
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• pp.729-736
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• 2017

This work investigates secure cluster-aided multi-hop randomize-and-forward networks. We present a hop-by-hop multi-hop transmission scheme with relay selection, which evaluates for each cluster the relays that can securely receive the message. We propose an analytical model to derive the secure connectivity probability (SCP) of the hop-by-hop transmission scheme. For comparison, we also analyze SCPs of traditional end-to-end transmission schemes with two relay-selection policies. We perform simulations, and our analytical results verify that the proposed hop-by-hop scheme is superior to end-to-end schemes, especially with a large number of hops or high eavesdropper channel quality. Numerical results also show that the proposed hop-by-hop scheme achieves near-optimal performance in terms of the SCP.

• ETRI Journal
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• v.34 no.3
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• pp.462-465
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• 2012

This letter proposes a new distributed scheduling scheme combined with routing to support the quality of service of real-time applications in wireless mesh networks. Next, this letter drives average end-to-end delay of the proposed scheduling scheme that sequentially schedules the slots on a path. Finally, this letter simulates the time division multiple access network for performance comparison. From the simulation results, when the average number of hops is 2.02, 2.66, 4.1, 4.75, and 6.3, the proposed sequential scheduling scheme reduces the average end-to-end delay by about 28%, 10%, 17%, 27%, and 30%, respectively, compared to the conventional random scheduling scheme.

• The Journal of Engineering Research
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• v.7 no.1
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• pp.37-51
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• 2005

An and hoc network is a collection of wireless mobile nodes forming a temporary network without the centralized administration. Due to the limited transmission range of wireless work interface, multiple networks "hops" maybe needed for one node to exchange data with adjacent node. In recent years, a variety of new routing protocol about ad hoc network was developed. This paper presents a new routing protocol based on the Dynamic Source Routing which is not suitable for the high mobility ad hoc network. The Enhanced DR adapts quickly to routing changes when node movement is frequent. When a trunk route is broken, this protocol will utilize the alternative route saved in the route to discovery quickly the new route. It improves the performance of the existing DSR algorithm, so that the negative impacts from weakness of DSR are reduced.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.138-143
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• 2005

A hierarchical tree structure of clusters has advantages for the network design due to its scalability and simple routing protocol. In this paper, the cluster tree routing protocol is studied for the wireless sensor network. From the numerical analysis results, the data aggregation in the intermediate nodes reduces the number of communication message and saves the energy of sensor nodes, but it may result in increased data traffic latency. And also the selection of cluster head can increase the relaying hops very high.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.1064-1074
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• 1997

In this paper we propose an every-other-row-connecting bilayered ShuffkeNet for optical WDM(wavelength division multiplexing) multihop networks. We calculate the diameter and the average number of hops of the proposed every-other-row-connecting bilayered ShuffleNet. Using the result, we also calcuate throughputs and delays of the proposed topology, which show higher efficiencies compared to the conventional ShuffleNet, the bilayered ShuffleNet and asymmetric bilayered ShuffleNet.

• Natural Product Sciences
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• v.14 no.4
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• pp.269-273
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• 2008

Microbial transformation of isoxanthohumol (1), a prenylated flavanone from hops, has resulted in the production of a pair of glucosylated derivatives. The structures of these compounds were elucidated to be (2S)-5-methoxy-8-prenylnaringenin 7-O-${\beta}$-D-glucopyranoside (2) and (2R)-5-methoxy-8-prenylnaringenin 7-O-${\beta}$-Dglucopyranoside (3) based on the spectroscopic analyses.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.2
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• pp.28-34
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• 2008

This paper reports the problem in the previous routing protocol, EAR, and proposes an energy aware routing protocol to solve the problem in it. Proposed routing protocol considers the number of hops, the possibility of node exhaustion, and the node energy amount at the same time from the source to the sink. Thereby, it could efficiently solve the potential network separation problem and the sensing hole problem in EAR. Proposed routing protocol could remove the problems in the previous routing protocols but it still gets the advantages in them.