Multi-Hop Clock Synchronization Based on Robust Reference Node Selection for Ship Ad-Hoc Network

Su, Xin,Hui, Bing,Chang, KyungHi The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.1

Ship ad-hoc network (SANET) extends the coverage of the maritime communication among ships with the reduced cost. To fulfill the growing demands of real-time services, the SANET requires an efficient clock time synchronization algorithm which has not been carefully investigated under the ad-hoc maritime environment. This is mainly because the conventional algorithms only suggest to decrease the beacon collision probability that diminishes the clock drift among the units. However, the SANET is a very large-scale network in terms of geographic scope, e.g., with 100 km coverage. The key factor to affect the synchronization performance is the signal propagation delay, which has not being carefully considered in the existing algorithms. Therefore, it requires a robust multi-hop synchronization algorithm to support the communication among hundreds of the ships under the maritime environment. The proposed algorithm has to face and overcome several challenges, i.e., physical clock, e.g., coordinated universal time (UTC)/global positioning system (GPS) unavailable due to the atrocious weather, network link stability, and large propagation delay in the SANET. In this paper, we propose a logical clock synchronization algorithm with multi-hop function for the SANET, namely multi-hop clock synchronization for SANET (MCSS). It works in an ad-hoc manner in case of no UTC/GPS being available, and the multi-hop function makes sure the link stability of the network. For the proposed MCSS, the synchronization time reference nodes (STRNs) are efficiently selected by considering the propagation delay, and the beacon collision can be decreased by the combination of adaptive timing synchronization procedure (ATSP) with the proposed STRN selection procedure. Based on the simulation results, we finalize the multi-hop frame structure of the SANET by considering the clock synchronization, where the physical layer parameters are contrived to meet the requirements of target applications.

Standardizing and optimizing acupuncture treatment for irritable bowel syndrome: A Delphi expert consensus study

Xin-Tong Su,Wang Li-Qiong,Zhang Na,Li Jin-Ling,Qi Ling-Yu,Wang Yu,Jing-Wen Yang,Guang-Xia Shi,Cun-Zhi Liu 한국한의학연구원 2021 Integrative Medicine Research Vol.10 No.3

Background: Acupuncture has been widely utilized for irritable bowel syndrome (IBS). However, heterogeneity is large among therapeutic strategies and protocols. The aim of this study was to propose some down-to-earth recommendations and establish an optimized protocol for acupuncture practice in IBS. Methods: A panel of 74 traditional Chinese medicine (TCM) acupuncturists participated in clinical issue investigation. Subsequently, systematic reviews concerning acupuncture for IBS were screened within 3 databases. An initial consensus questionnaire was formed from the results of clinical issue investigation and literature review. Ultimately, a Delphi vote was carried out to determine these issues. 30 authoritative experts with extensive experience were requested to respond with agreement, neutrality, or disagreement for the items. Consensus achievement on a given item was defined as greater than 80% agreement. Results: Following a 2-round Delphi survey, there were 19 items reaching consensus; of which 5 items (26.32%) achieved thorough consensus, and significant agreement was reached for the other 14 items. These items can be classified into the 3 major domains: 1) clinical outcomes that acupuncture can bring for favorable intervention population (5 items), 2) suitable therapeutic principles and parameters of acupuncture (13 items), 3) possible adverse events in the treatment (1 item). Conclusion: Without any ready-made guidelines and lacking of homogeneity in the published literatures, such expert consensus could be valuable for TCM acupuncturists in daily practice and patients with IBS to obtain appropriate and standardized acupuncture treatment. In addition, it also points out the clinical focus which need to be further explored in future trials.

High-rate Technology for Near Field Communication

Xin Su,Bing Hui,KyungHi Chang,InGi Lim 한국통신학회 2011 한국통신학회 학술대회논문집 Vol.2011 No.11

Density Aware Energy Efficient Clustering Protocol for Normally Distributed Sensor Networks

Su, Xin,Choi, Dong-Min,Moh, Sang-Man,Chung, Il-Yong Korea Multimedia Society 2010 멀티미디어학회논문지 Vol.13 No.6

In wireless sensor networks (WSNs), cluster based data routing protocols have the advantages of reducing energy consumption and link maintenance cost. Unfortunately, most of clustering protocols have been designed for uniformly distributed sensor networks. However, some urgent situations do not allow thousands of sensor nodes being deployed uniformly. For example, air vehicles or balloons may take the responsibility for deploying sensor nodes hence leading a normally distributed topology. In order to improve energy efficiency in such sensor networks, in this paper, we propose a new cluster formation algorithm named DAEEC (Density Aware Energy-Efficient Clustering). In this algorithm, we define two kinds of clusters: Low Density (LD) clusters and High Density (HD) clusters. They are determined by the number of nodes participated in one cluster. During the data routing period, the HD clusters help the neighbor LD clusters to forward the sensed data to the central base station. Thus, DAEEC can distribute the energy dissipation evenly among all sensor nodes by considering the deployment density to improve network lifetime and average energy savings. Moreover, because the HD clusters are densely deployed they can work in a manner of our former algorithm EEVAR (Energy Efficient Variable Area Routing Protocol) to save energy. According to the performance analysis result, DAEEC outperforms the conventional data routing schemes in terms of energy consumption and network lifetime.

Multi-Hop Clock Synchronization Based on Robust Reference Node Selection for Ship Ad-Hoc Network

Xin Su,Bing Hui,장경희 한국통신학회 2016 Journal of communications and networks Vol.18 No.1

Ship ad-hoc network (SANET) extends the coverage ofthe maritime communication among ships with the reduced cost. To fulfill the growing demands of real-time services, the SANET requiresan efficient clock time synchronization algorithm which hasnot been carefully investigated under the ad-hoc maritime environment. This is mainly because the conventional algorithms only suggestto decrease the beacon collision probability that diminishes theclock drift among the units. However, the SANET is a very largescalenetwork in terms of geographic scope, e.g., with 100 kmcoverage. The key factor to affect the synchronization performance is thesignal propagation delay, which has not being carefully consideredin the existing algorithms. Therefore, it requires a robustmulti-hopsynchronization algorithm to support the communication amonghundreds of the ships under the maritime environment. The proposedalgorithm has to face and overcome several challenges, i.e.,physical clock, e.g., coordinated universal time (UTC)/ global positioningsystem (GPS) unavailable due to the atrocious weather, networklink stability, and large propagation delay in the SANET. Inthis paper, we propose a logical clock synchronization algorithmwith multi-hop function for the SANET, namely multi-hop clocksynchronization for SANET (MCSS). It works in an ad-hoc mannerin case of no UTC/GPS being available, and themulti-hop functionmakes sure the link stability of the network. For the proposedMCSS, the synchronization time reference nodes (STRNs) are effi-ciently selected by considering the propagation delay, and the beaconcollision can be decreased by the combination of adaptive timingsynchronization procedure (ATSP) with the proposed STRN selectionprocedure. Based on the simulation results, we finalize themulti-hop frame structure of the SANET by considering the clocksynchronization, where the physical layer parameters are contrivedto meet the requirements of target applications.

A Survey on Multiple Channel protocols for Ad Hoc Wireless Networks

( Xin Su ),( Seokjoo Shin ),( Ilyong Chung ) 한국정보처리학회 2009 한국정보처리학회 학술대회논문집 Vol.16 No.1

Wireless ad hoc networks often suffer from rapidly degrading performance with the number of user increases in the network. One of the major reasons for this rapid degradation of performance is the fact that users are sharing a single channel. Obviously, the problem of using single shared channel schemes is that the probability of collision increases with the number of nodes. Fortunately, it is possible to solve this problem with multi-channel approaches. Due to the especial properties of multiple channels, using the multiple channels is more efficient than single channel because it enhances the capacity of the channel and reduces the error rate during data transmission. Some multi-channel schemes us one dedicated channel for control packets and one separate channel for data transmissions. On the other hand, another protocols use more than two channels for data transmissions. This paper summarizes six multiple channel protocols based on these two kinds of schemes. Then we compare them and discuss the research challenge of multiple channel protocols.

Case Study for Ship Ad-hoc Networks under a Maritime Channel Model in Coastline Areas

( Xin Su ),( Haifeng Yu ),( Kyunghi Chang ),( Seung-geun Kim ),( Yong-kon Lim ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.10

ITU-R M.1842-1, as a well-known specification dedicated to maritime mobile applications, has standardized wireless transmission protocols according to the particular characteristics of a maritime communications scenario. A time division multiple access (TDMA) frame structure, along with modulation schemes to achieve a high data rate, has been described clearly in ITU-R M.1842-1. However, several specification items are still under “to be decided” status, which brings ambiguity to research works. In addition, the current version of ITU-R M.1842-1 is focused mainly on maritime transmissions in open-sea areas, where the cyclic prefix (CP) is set to zero and only 16-QAM is used in the multi-carrier (MC) system. System performance might be dramatically degraded in coastline areas due to the inter-symbol interference (ISI) caused by selective fading. This is because there is a higher probability that the signal will be reflected by obstacles in coastline areas. In this paper, we introduce the transmission resource block (TRB) dedicated to ITU-R M.1842-1 for a ship ad-hoc network (SANET), where the pilot pattern of TRB is based on the terrestrial trunked radio (TETRA). After that, we evaluated SANET performance under the maritime channel model in a coastline area. In order to avoid noise amplification and to overcome the ISI caused by selective fading, several strategies are suggested and compared in the channel estimation and equalization procedures, where the link-level simulation results finally validate our proposals.

Space-Time Block Coding with Beamforming for Triple-Polarized Uniform Linear Array Systems

Su, Xin,Chang, Kyung Hi Hindawi Limited 2015 International journal of antennas and propagation Vol.2015 No.-

<P>Generally, space-time block coding (STBC) and beamforming (BF) gains cannot be obtained simultaneously because the former performs well under a low correlated MIMO channel, and the latter works efficiently in an environment with high correlation. However, array systems with antenna polarization have the potential to achieve gains with both techniques simultaneously because the cross-branch links in the system are usually uncorrelated. The cross-array links, on the other hand, can be highly correlated by setting the array element space equal to, or less than, a half-wavelength. This paper proposes a scheme to explore STBC and BF simultaneously via a triple-polarized uniform linear array (TPULA) system. The proposed scheme was verified based on the Long Term Evolution-Advanced (LTE-A) specification under a polarized MIMO (PMIMO) channel model, and therewith, the simulation results confirmed the validity of our proposed scheme.</P>

Single Nucleotide Polymorphisms of Toll-Like Receptor 7 and Toll-Like Receptor 9 in Hepatitis C Virus Infection Patients from Central China

Xin-su Wei,Ping-an Zhang,Chuan-dong Wei,Yong-qing Tong,Cheng-liang Zhu 연세대학교의과대학 2014 Yonsei medical journal Vol.55 No.2

Purpose: To analyze the correlation of polymorphisms of toll-like receptor 7 (TLR7) (rs179009) and toll-like receptor 9 (TLR9) (rs187084) in hepatitis C virus (HCV) infections in the Han population. Materials and Methods: The genotypes of TLR7IVS2-151 in HCV infection were detected by Sanger sequencing using polymerase chain reaction-restriction fragment length polymorphism to determine the TLR9 T-1486C single nucleotide polymorphisms (SNP) for all enrolled patients. Results: We found no significant difference between males with spontaneousclearance of HCV versus those chronically infected [χ²=2.71, p=0.10, odd ratios(OR)=0.58, 95% confidence interval (CI) 0.31-1.11]. However, significant differences were found for the distribution of TLR7 (rs179009) in females (χ²=9.46, p=0.01). In females, a significant difference was also found between chronic hepatitis C and those with spontaneous clearance of HCV in terms of TLR7 IVS2-151G/A allele frequencies (χ²=9.50, p=0.00, OR=0.46, 95% CI 0.28-0.75). In HCV-infected patients, no significant association was found between the frequency of TLR9 genotypes and alleles. Conclusion: The site of TLR7 IVS2-151 (rs179009) G/A may be a factor for susceptibility of chronic HCV in the femaleHan population. TLR9T-1486C (rs18084) SNP may not play a major role in HCV infection. However, individual risk profiles for HCV infection did vary by sex and this relationship should be further investigated.

A Survey on Smart Dust Motes for Wireless Sensor Networks

Xin Su,Sangman Moh,Ilyong Chung 한국멀티미디어학회 2009 한국멀티미디어학회 학술발표논문집 Vol.2009 No.1

A sensor network consists of a large number of sensing devices capable of detecting waves of sound, heat, magnetism and so on. Each sensing device needs to collaborate with its neighboring devices to perform a given task by disseminating data through the network. We call these devices Smart dust Motes, which an attractive architecture for sensor networks is to have each sensing device mounted on a small computer. They have characteristics including low-power consumption, small size, and flexibility. Smart dust motes are battery-powered, and can communicate in a wireless fashion by broadcasting messages over radio frequency. They are energy constrained and range of their radio transmission is limited to their neighborhood. So, they form a multi-hop network to deliver information packets. In this paper, we survey different kinds of modem smart dust motes and give briefly specification by using a comparative table.