China Ji Liang University

Hangzhou, China

China Ji Liang University

Hangzhou, China
Time filter
Source Type

Wang Y.,China Ji Liang University | Wang Y.,Harbin Institute of Technology | Zhang A.,China Ji Liang University | Ma J.,Harbin Institute of Technology
Optical Engineering | Year: 2017

Minimum-shift keying (MSK) has the advantages of constant envelope, continuous phase, and high spectral efficiency, and it is applied in radio communication and optical fiber communication. MSK modulation of coherent detection is proposed in the ground-to-satellite laser communication system; in addition, considering the inherent noise of uplink, such as intensity scintillation and beam wander, the communication performance of the MSK modulation system with coherent detection is studied in the uplink ground-to-satellite laser. Based on the gamma-gamma channel model, the closed form of bit error rate (BER) of MSK modulation with coherent detection is derived. In weak, medium, and strong turbulence, the BER performance of the MSK modulation system is simulated and analyzed. To meet the requirements of the ground-to-satellite coherent MSK system to optimize the parameters and configuration of the transmitter and receiver, the influence of the beam divergence angle, the zenith angle, the transmitter beam radius, and the receiver diameter are studied. © 2017 Society of Photo-Optical Instrumentation Engineers (SPIE).

Xiao B.,China Ji Liang University | Gu M.,China Ji Liang University | Xiao S.,Technical University of Denmark
Applied Optics | Year: 2017

Tunable terahertz absorbers composed of periodically cross-shaped graphene arrays with the ability to achieve nearunity absorbance are proposed and studied. Our results demonstrate that the bandwidth of absorption rate above 90% can reach up to 1.13 terahertz by use of a single layer of cross-shaped graphene arrays. By simply stacking the double layer cross-shaped graphene with careful design, the working bandwidth can be broadened compared with the single-layer graphene-based absorber. The proposed absorbers have the properties of being polarization insensitive and having large angle tolerance, and the tunability of the Fermi level in graphene allows us to realize tunable terahertz absorbers with potential interest in integrated terahertz optoelectronic devices. © 2017 Optical Society of America.

Zhang B.,China Ji Liang University | Wang Q.,China Ji Liang University | Tang C.,China Ji Liang University | Wang J.,China Ji Liang University
IOP Conference Series: Materials Science and Engineering | Year: 2017

A robot motion control method is presented for intelligent welding processes of complex spatial free-form curve seams based on the laser tracking sensor. First, calculate the tip position of the welding torch according to the velocity of the torch and the seam trajectory detected by the sensor. Then, search the optimal pose of the torch under constraints using genetic algorithms. As a result, the intersection point of the weld seam and the laser plane of the sensor is within the detectable range of the sensor. Meanwhile, the angle between the axis of the welding torch and the tangent of the weld seam meets the requirements. The feasibility of the control method is proved by simulation. © Published under licence by IOP Publishing Ltd.

Tan J.,China Ji Liang University | Wang Y.,China Ji Liang University | Zhang M.,China Ji Liang University
Chinese Journal of Sensors and Actuators | Year: 2014

The more reliability and timeliness are required in wireless body area networks (WBAN) compared to traditional wireless sensor networks, and all the packets are needed to be reliable. A timely and reliable protocol (AODV-RT) is presented, considering limited memory resource of the node and the priority of the WBAN data, it guarantees reliability and timeliness utilizing error recovery of E2E (End-To-End), HBH (Hop-By-Hop), and combining E2E with HBH. The alarm data, which has highest priority, is cached at each node along the route path. The HBH error recovery is provided firstly; Then the error recovery combining E2E with HBH is provided for lower RSSI (Received Signal Strength Indicator)node to caching higher priority data packet at the previous node, and finally the ETE error recovery is adopted for lower priority packet. The performance analysis and simulation experiment indicate that our protocol is more advantaged then similar MAODV-SIM in packet delivery ratio, end-to-end delay and energy consumption.

Zhou L.H.,China Ji Liang University | Xu X.H.,China Ji Liang University | Yu D.Z.,China Ji Liang University
Applied Mechanics and Materials | Year: 2014

This paper presents a methodology for diagnostics of fixture failures in multistation assembly processes. Diagnosis matrix equation is established by state space equation and measurement equation, which study the conditions of deviation source diagnosis. The determination method of deviation source diagnosis is obtained. 3-D scanner is used to measure the key data. A case study illustrates the proposed method. © (2014) Trans Tech Publications, Switzerland.

Chen H.Y.,China Ji Liang University | Shen H.Y.,China Ji Liang University | Ying Y.H.,China Ji Liang University
Proceedings - 2014 IEEE Workshop on Electronics, Computer and Applications, IWECA 2014 | Year: 2014

Particle concentration detection sensor which is based on light scattering particle concentration theory has high reliability, fast and easy using and so on. However, it demands to extract the small signal in the background of the large noise. It requires to use the modulated light source, so this paper design the circuit, it uses the digital multiplier and make the sensor work more steady and more fast. Tirst the signal goes through the preamplifier circuit, then goes through the six-order band-pass filter, the last the band limited weak signal should be locked by lock-in amplifier. The paper offers the good method to detect the weak signal in the big noise ground. © 2014 IEEE.

Guo M.Y.,China Ji Liang University | Lou H.L.,China Ji Liang University
Applied Mechanics and Materials | Year: 2013

In this paper, six sigma methods were used in bearing ring grinding process improvement. In the improvement, bearing outer ring roundness error was selected as the assessment index, and exsiting problems in grinding process were defined, roundness error of bearing outer ring was measured.One-way analysis of variance was applied to analyze the test results, it indicates that workpiece center height, guide wheel tilt angle and grinding wheel balance are the three main factors that affecting roundness error.According to this analysis, orthogonal experiment was designed. The results show that grinding wheel balance, guide wheel tilt angle and workpiece center height on the impact of roundness error are in descending order. On this basis, a series of measures were carried out to control these three parameters. Uitimately, the grinding process capability index is increased from 0.88 to 1.43, and the target of improvement are achieved. © (2013) Trans Tech Publications, Switzerland.

Tan J.,China Ji Liang University | Zhang M.,China Ji Liang University
Chinese Journal of Sensors and Actuators | Year: 2013

This paper proposes an energy-efficient reprogramming protocol with selection of scope. Firstly, based on the application that needs to be updated, node's residual energy, effective degree and link quality, this protocol selects a subset of the nodes in the network as core nodes to create a virtual backbone. Then in order to disseminate data, it employs a two phase approach, in which the software image is delivered to the core nodes by pipeline in the first phase, and to the needed ordinary nodes parallelly in the second phase, reduces the number of nodes involved in the reprogramming efficiently, saves energy and achieves the selection of scope. And in addition to further reducing energy consumption, a coordinated sleep schedule is introduced. The performance analysis and simulation experiment indicate that, the average delay and energy consumption in this protocol drops 5.6%-24.8% and 5.1%-27.7% approximately compared with ThreeStages and Aqueduct.

Jin T.,China Ji Liang University | Yijing W.,China Ji Liang University
International Journal of Security and its Applications | Year: 2014

The data security and privacy are key issues, as well as the security measures of clinical application are desired to be simple operations of "plug and play" for wireless body area networks (BAN). In this paper, a secure multi-hop data transmission protocol based on combination of node's clock characteristics and properties of the BAN/BSN is presented without relying on any pre-distributed secret information. First, through exchanging clock frequency (CF) among node x , its neighbor i and sink in a safe environment, the pair-wise Kx between node x and sink is generated with CF of x and is used to encrypt data sensed by x ; the pair-wise Kxi or Kix between x and i is generated with clock skew of two nodes is used to encrypt route information; Second, the RREQ and RREP messages of AODV protocol is improved, and creates a secure route only composed of legal nodes through authenticating nodes with CFs of two adjacent nodes; Finally, the data packet produced by source x is divided into Data1 and Data2, Data2 is the being sensed data encrypted with Kx , and Data1 encrypted with Kxi or Kix includes source, destination, generated time of data and other information, the intermediate node needs to encrypt Data1again after decrypting Data1 to obtain route information, and transmits this data packet to sink with hop-by-hop. This protocol has good security in dynamics and accuracy of keys, avoiding passive and active attacks, preventing node capture and supporting new node joining through security analysis, and has accepted overheads of memory, computation and energy consumption by means of performance analysis; it satisfies the requirements of "plug and play" without added node's hardware and pre-load any keys, makes the complicated data security and privacy in the BAN/BSN become operable easily and practicable strongly. © 2014 SERSC.

Liu L.,China Ji Liang University | Tao J.,China Ji Liang University
Advanced Materials Research | Year: 2012

This paper brings public participate into the analysis framework and analyzes its effectiveness on the environment pollution. The studies have shown that the effectiveness of public participation on industrial wastes has relevant to the type of the industrial pollutants. © (2012) Trans Tech Publications, Switzerland.

Loading China Ji Liang University collaborators
Loading China Ji Liang University collaborators