Applied Mechanics and Materials Vols. 236-237

Abstract: A new theoretical model for wavelength conversion based on XGM in fiber grating external cavity lasers is presented. The expression of mutual coupling parameter βm which indicates the efficiency of the wavelength conversion.was introduced in the model and and confirmed by numerical simulation. The theoretical analysis showed that the mutual coupling parameter βm is decided by intensity and frequency interval of CW light and the IM light, and the simulation results showed that the larger βm was, the better wavelength conversion was.

Abstract: This paper presents a solution of mobile payment based on SWP/HCI (ETSI) implemented with Micro SD card connected to an NFC-enabled mobile phone. Connection scenarios of the solution are described. Moreover, SWP/HCI protocol architecture is given. Programming and optimization of this solution is analyzed as well. We implement the functions and procedures using C plus plus language on ARM 7 platform. This solution complies with the development of NFC technology and compatible with the existing POS payment system terminals. And after optimization, the occupying RAM space of the codes is reduced by 74%.

Abstract: In on-line inspection for products based on machine vision, contrast between product defects and background is not always stable because of the discrepancy of environment where images are captured and the type, batch and innate structure of products to be detected. To perform accurate detection, image is usually divided into several parts which are of same gray value and later on sub-blocks the analysis for defected region where sudden gray value changes are occurring. The crucial step here is to have accurate regional image segmentation. Traditional edge detection is unlikely to ensure its accuracy, and at the same time, complicated image segmentation algorithms are time-consuming and cannot meet needs of real-time manufacturing. Images captured during on-line detection is relatively stable in structure. A new real-time image fast segmentation algorithm is proposed in this dissertation. This algorithm, combining with use of local image enhancement algorithm, morphological operation of simple structural operators and image thinning technology, can accurately find regions boundry of uniform region. Later, on-line image segmentation can be fulfilled by means of simple addition and subtraction for regions. This algorithm has been successfully applied to on-line capsule inspection. Experiments show that it can satisfy the need of on-line detection both with speed and accuracy.

Abstract: In order to suppress Tx-to-Rx carrier leakage in Radio Frequency Identification (RFID) system, this paper proposes the method of carrier leakage canceler of rate race circuit. It uses the two outputs of rate race circuit as antenna port and reflection port, and the imperfect isolation (Tx-to-Rx) and the reflection of antenna mismatch are suppressed in the receiver by adjusting the reflection coefficient of reflection port. Simulation shows that using rate race carrier’s cancellation circuit can perfectly suppress the carrier leakage in receiving circuit, the carrier’s suppression ration reaches 71.7dB which is 36dB higher than traditional circulator. Finally, the practice circuit is tested, and the result of test shows that carrier suppresses 61dB, which has a good application value in engineering

Abstract: Millimeter-wave (MMW) radiometric imaging system is widely used in the field of military and civil affairs. It can be used to detect concealed objects hidden under clothing. Based on MMW radiation imaging method and morphology theory, we presented a complex morphology filter to do the image pretreatment. Then used the Canny operator to extract features from concealed objects. The results show that the morphology algorithm can improve the quality of radiometric images. Meanwhile, Canny algorithm can detect the edges of object well.

Abstract: In order to make a convenient interface to the complexity of the timing of high-speed, high-capacity storage medium applications, a new design has been proposed for the interface device of storage media with FIFO feature based on DDRII SDRAM by this thesis. At first, the principles and implementation of DDRII SDRAM controller are introduced. Then the memory interface module has been designed based on the time-sharing technique of DDRII SDRAM. Finally, the principles of the interface controller module have been deeply analyzed and implemented by functional simulation through the Quartus II software and FPGA hardware verification. Through stimulation and verification, the high-speed memory interface controller module based on DDRII SDRAM implemented the bi-directional data transfer and interaction between DDRII memory and FPGA, which has a certain value of practical application.

Abstract: This paper introduces the first wireless sensor network node localization in two ways, one is based on the RSSI ranging approach, and the other is based on the weighted centric location algorithm, as a result of environmental factors, the same RSSI value the distance ，but the corresponding values are not always the same, these two methods do not consider the environmental impact to the RSSI value. Therefore, we consider combining the distance and signal strength information as a reference to correct each beacon node weights， in order to improve positioning accuracy.

Abstract: It is the key step for real-time image processing of beacon to complete the pointing, acquisition and tracking course between the optical communication terminals. The segmentation and extraction of beacon is the most difficult problem for the sequence image processing, a kind of adaptive threshold segmentation method is put forward on the basis of Otsu algorithm , in the improved algorithm, the image processing is divided into two parts: firstly, it is to identify potential target in a single frame; the secondly, it is to detect beacon image in a region of interesting . Finally, the kalman model is applied to accomplish the tracking of beacon, the experimental result shows that the Otsu algorithm overcomes the disadvantage of incomplete information for traditional algorithm, therefore, it is beneficial to improve the tracking ability of system．

Abstract: Wireless Sensor Networks (WSNs) provide a valuable capability to autonomously monitor remote activities. Their limited resources challenge WSN medium access control (MAC) layer designers to adequately support network services while conserving limited battery power. We expect sensor networks to be deployed in an ad hoc fashion, with individual nodes remaining largely inactive for long periods of time, but then becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in almost every way: energy conservation and self-configuration are primary goals. This paper proposes M-MAC, a medium access control protocol designed for medical wireless sensor networks. M-MAC’s centre management function offers significant energy savings by wiping off contention and keeping nodes sleeping all the time except awaking to send its Data package. All Slave Node(SN) need only communicate with a specific Master Node(MN) in a group and due to close range, routing is unnecessary. The MN acts as scheduler and when receives a Data package from a SN, it will indicate the SN how long it should be asleep and what it should do after awaking. Period is introduced as the time windows and it is divided into Frame Time. Every MN occupies a unique Frame Time and this is decided by its MAC address. Then the Frame Time separates into smaller Slot Time and it is the atomic time span for SN exchanging data with MN. Practice has proved that the M-MAC protocol is effective in our medical application and it can extend the lifetime of SN greatly

Abstract: The preconditions of storage pre-schedule and real-time schedule management are wireless access and mobility support technology in aluminum profile logistic, which is vital for the automated storage/retrieval system(AS/RS) and logistics processes, such as intelligent warehousing and shipment. Understandings characters of the current wireless access technologies, applicability of networking mobility schemes, and their cooperation or compatibility with the Internet of things, decide the AS/RS and logistics structure and its whole efficiency. So the relational technologies and schemes are introduced in this paper from bottom to top according to Open System Interconnect seven layers protocols. It reveals that integration of multi-technologies was widely adopted in project implementation, which can be helpful to achieve high quality of mobile Internet access with lesser costs. Moreover, the feasibility of handover simplification and quality of service construction imply the success of schemes in design. Finally the strategic impact factors of the networking mobility support technology for AS/RS and logistics are concluded as overlapping coverage network optimization, delay tolerant network, and quality of service system based on user behavior.