Performance Improvement of Delay-Tolerant Networks with Mobility Control under Group Mobility

( Ling Fu Xie ),( Peter Han Joo Chong ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.6

This paper considers mobility control to improve packet delivery in delay-tolerant networks (DTNs) under group mobility. Based on the group structure in group mobility, we propose two mobility control techniques; group formation enforcement and group purposeful movement. Both techniques can be used to increase the contact opportunities between groups by extending the group`s reachability. In addition, they can be easily integrated into some existing DTN routing schemes under group mobility to effectively expedite the packet delivery. This paper is divided into 2 parts. First, we study how our proposed mobility control schemes reduce the packet delivery delay in DTNs by integrating them into one simple routing scheme called group-epidemic routing (G-ER). For each scheme, we analytically derive the cumulative density function of the packet delivery delay to show how it can effectively reduce the packet delivery delay. Then, based on our second proposed technique, the group purposeful movement, we design a new DTN routing scheme, called purposeful movement assisted routing (PMAR), to further reduce the packet delay. Extensive simulations in NS2 have been conducted to show the significant improvement of PMAR over G-ER under different practical network conditions.

A method of measuring acoustic absorption coefficient of a material specimen using a dynamic microphone

Jin Xie,Shih-Fu Ling 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.3

This paper reports the development of a method for measuring the absorption coefficient of a material specimen mounted at one end of a planar wave tube using a dynamic microphone at the other end. In the proposed method, the dynamic microphone mounted is used as an actuator (loudspeaker) to generate sound waves and simultaneously performs as a probe to sense acoustic impedance at the same point. For the electro-mechanical acoustical system formed by the dynamic microphone and the tube, a “transduction matrix” is introduced to relate the input electrical variables (voltage and current) and the output acoustical variables (pressure and particle velocity). Once the matrix is calibrated, probing the input voltage and current to the dynamic microphone alone allows quantitative evaluation of the acoustic impedance of material specimen, from which absorption coefficient of the material is calculated. Measurements of fully-reflected end,anechoic end and a porous material specimen are carried out and compared to the results obtained by the conventional transfer function method. It is found that the results match well with each other in a frequency range depending on the length of the tube

Electrical impedance as signal to monitor healthy state of eardrum-like membranes

Jin Xie,Shih-Fu Ling 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.8

Eardrum perforation is viewed as one kind of structural damage occurring in human being, which will cause loss of hearing when the damage becomes serious. This paper describes a preliminary concept to detect damage of eardrum-like membranes through measuring electrical impedance of a dynamic microphone. The dynamic microphone is inserted in one end of an ear canal-like tube and the eardrum-like membrane is attached at the other end of tube. Holes with different size are drilled in the membranes to represent the different damage levels. The electrical impedance of dynamic microphone is directly related to the mechanical impedance of the membrane, and any change in the electrical impedance signal can be considered an indication of change in the membrane integrity. For the different damage levels of membrane, variation of electrical impedance from the dynamic microphone is observed in experiment. Features are extracted from the curves of electrical impedance and used to train an artificial neural network. Through the trained neural network, damage in membrane can be monitored even in its incipient stage, and the damage levels can be easily estimated, which indicates electrical impedance is a good signal for non-destructive evaluation of structural health.

Genetic Linkage of Genes for a Thermo-sensitive Genic Male Sterility in Maize: The genetic analysis of an TGMS Line Qiong-6ms in maize

Zhi Yuan Fu,Hui Ling Xie,Jian Sheng Li,Yan Min Hu,Zong Hua Liu,Zhong You He,Ji Hua Tang 한국유전학회 2008 Genes & Genomics Vol.30 No.6

Thermo-sensitive genic male sterile (TGMS) lines can provide new options for hybrid seed production using "two-line" system. A set of F2 and BC1 populations derived from the cross between Qiong-6ms and Dan958 were employed to analyze the inheritance of a TGMS line Qiong-6ms and map the TGMS genes in maize. The results demonstrated that the sterility of Qiong-6ms was governed by two duplicative recessive genes, named tms1 and tms2. The gene tms1 was mapped to chromosome 5 linked with the SSR markers umc1355, umc2302 and umc1784 at a distance of 3.0 cM, 1.3 cM and 0.9 cM respectively; while tms2 was localized on chromosome 3, linked with SSR markers bnlg1605 (0.5 cM) and umc2050 (4.2 cM). These markers, which are tightly linked with the tms1 and tms2 genes, will be helpful for marker assisted selection of TGMS lines in maize.

Baseline Total Metabolic Tumor Volume and Total Lesion Glycolysis Measured on 18F-FDG PET-CT Predict Outcomes in T-Cell Lymphoblastic Lymphoma

Xiaoyan Feng,Xin Wen,Ling Li,Zhenchang Sun,Xin Li,Lei Zhang,Jingjing Wu,Xiaorui Fu,Xinhua Wang,Hui Yu,Xinran Ma,Xudong Zhang,Xinli Xie,Xingmin Han,Mingzhi Zhang 대한암학회 2021 Cancer Research and Treatment Vol.53 No.3

Purpose There is no optimal prognostic model for T-cell lymphoblastic lymphoma (T-LBL). Here, we discussed the predictive value of total metabolic tumor volume (TMTV) and total lesion glycolysis (TLG) measured on 18F-fluorodeoxyglucose positron emission tomography–computed tomography (PET-CT) in T-LBL.Materials and Methods Thirty-seven treatment naïve T-LBL patients with PET-CT scans were enrolled. TMTV was obtained using the 41% maximum standardized uptake value (SUVmax) threshold method, and TLG was measured as metabolic tumor volume multiplied by the mean SUV. Progression-free survival (PFS) and overall survival (OS) were analyzed by Kaplan-Meier curves and compared by the log-rank test.Results The optimal cutoff values for SUVmax, TMTV, and TLG were 12.7, 302 cm3, and 890, respectively. A high SUVmax, TMTV, and TLG indicated a shorten PFS and OS. On multivariable analysis, TMTV ≥ 302 cm3, and central nervous system (CNS) involvement predicted inferior PFS, while high SUVmax, TLG and CNS involvement were associated with worse OS. Subsequently, we generated a risk model comprising high SUVmax, TMTV or TLG and CNS involvement, which stratified the population into three risk groups, which had significantly different median PFS of not reached, 14 months, and 7 months for low-risk group, mediate-risk group, and high-risk group, respectively (p < 0.001). Median OS were not reached, 27 months, and 13 months, respectively (p < 0.001).Conclusion Baseline SUVmax, TMTV, and TLG measured on PET-CT are strong predictors of worse outcome in T-LBL. A risk model integrating these three parameters with CNS involvement identifies patients at high risk of disease progression.

Optical Triangular Waveform Generation with Alterable Symmetry Index Based on a Cascaded SD-MZM and Polarization Beam Splitter-combiner Architecture

Dun Sheng Shang,Guang Fu Bai,Jian Tang,Yan Ling Tang,Guang Xin Wang,Nian Xie 한국광학회 2023 Current Optics and Photonics Vol.7 No.5

A scheme is proposed to generate triangular waveforms with alterable symmetry. The key component is a cascaded single-drive Mach-Zehnder modulator (SD-MZM) and optical polarization beam splittercombiner architecture. In this triangular waveform generator, the bias-induced phase shift, modulation index and controllable delay difference are changeable. To generate triangular waveform signals with different symmetry indexes, different combinations of these variables are selected. Compared with the previous schemes, this generator just contains one SD-MZM and the balanced photodetector (BPD) is not needed, which means the costs and energy consumption are significantly reduced. The operation principle of this triangular waveform generator has been theoretically analyzed, and the corresponding simulation is conducted. Based on the theoretical and simulated results, some experiments are demonstrated to prove the validity of the scheme. The triangular waveform signals with a symmetry factor range of 20–80% are generated. Both experiment and theory prove the feasibility of this method.