A custom-made computer program, SWIMRT, to construct "multileaf collimator (MLC) machine" file for intensity-modulated radiotherapy (IMRT) fluence maps was developed using MATLAB (R) and the slidingwindow a...
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A custom-made computer program, SWIMRT, to construct "multileaf collimator (MLC) machine" file for intensity-modulated radiotherapy (IMRT) fluence maps was developed using MATLAB (R) and the sliding window algorithm. The user can either import a fluence map with a graphical file format created by an external treatment-planning system such as Pinnacle3 or create his or her own fluence map using the matrix editor in the program. Through comprehensive calibrations of the dose and the dimension of the imported fluence field, the user can use associated image-processing tools such as field resizing and edge trimming to modify the imported map. When the processed fluence map is suitable, a "MLC machine" file is generated for our Varian 21 EX linear accelerator with a 120-leaf Millennium MLC. This machine file is transferred to the MLC console of the LINAC to control the continuous motions of the leaves during beam irradiation. An IMRT field is then irradiated with the 2D intensity profiles, and the irradiated profiles are compared to the imported or modified fluence map. This program was verified and tested using film dosimetry to address the following uncertainties: (1) the mechanical limitation due to the leaf width and maximum traveling speed, and (2) the dosimetric limitation due to the leaf leakage/transmission and penumbra effect. Because the fluence map can be edited, resized, and processed according to the requirement of a study, SWIMRT is essential in studying and investigating the IMRT technique using the sliding window algorithm. Using this program, future work on the algorithm may include redistributing the time space between segmental fields to enhance the fluence resolution, and readjusting the timing of each leaf during delivery to avoid small fields. Possible clinical utilities and examples for SWIMRT are given in this paper.
To improve the safety of conventional IC card consumption, this paper presents video monitoring technology applied to IC card consumption. During the IC card spending, the video surveillance records the entire consump...
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To improve the safety of conventional IC card consumption, this paper presents video monitoring technology applied to IC card consumption. During the IC card spending, the video surveillance records the entire consumptive process, and captures image. Videos shot detection, extract key frame, calculate key frames feature, cluster based on the characteristics of key frames, index with videos that are collected from video surveillance. Contrast the image with the key frame which is stored in database, users can quickly retrieve video clips. To a certain extent, ensure consumption safety. System using the Flex-based RIA technologies can effectively balance client and server computing load.
Turbo coding is a powerful coding technique that can provide highly reliable data transmission at extremely low signal-to-noise ratios. Owing to the computational complexity of the employed decoding algorithm, the rea...
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Turbo coding is a powerful coding technique that can provide highly reliable data transmission at extremely low signal-to-noise ratios. Owing to the computational complexity of the employed decoding algorithm, the realization of turbo decoders usually takes a large amount of memory space and potentially long decoding delay. Therefore, an efficient memory management strategy becomes one of the key factors toward successfully implementing turbo decoders. This paper focuses on the development of general structures for efficient memory management of turbo decoders employing the sliding-window (Log-)MAP algorithm. Three different structures and the associated mathematic representations are derived to evaluate the required memory size, average decoding rate, and latency based on the speed and the number of the adopted processors. Comparative results show the dependency of the resulting performance based on a set of parameters;thus provide useful and general information on practical implementations of turbo decoders.
Turbo codes have received tremendous attention and have commenced their practical applications due to their excellent error-correcting capability. Investigation of efficient iterative decoder realizations is of partic...
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Turbo codes have received tremendous attention and have commenced their practical applications due to their excellent error-correcting capability. Investigation of efficient iterative decoder realizations is of particular interest because the underlying soft-input soft-output decoding algorithms usually lead to highly complicated implementation. This paper describes the architectural design and analysis of sliding-window (SW) Log-MAP decoders in terms of a set of predetermined parameters. The derived mathematical representations can be applied to construct a variety of VLSI architectures for different applications. Based on our development, a SW-Log-MAP decoder complying with the specification of third-generation mobile radio systems is realized to demonstrate the performance tradeoffs among latency, average decoding rate, area/computation complexity, and memory power consumption. This paper thus provides useful and general information on practical implementation of SW-Log-MAP decoders.
Transformers are usually subjected to lightning impulse tests after assembly for assessment of their insulation strength. In the case of a fault the resulting winding current gets changed to a certain extent. The patt...
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Transformers are usually subjected to lightning impulse tests after assembly for assessment of their insulation strength. In the case of a fault the resulting winding current gets changed to a certain extent. The pattern of the fault currents depends on the type of fault and its location along the length of the winding. This paper describes the application of the concept of fractal geometry to analyze the properties of fault currents. Fractal features such as fractal dimension, lacunarity used for image surface recognition and the sliding window algorithm used for fractal analysis of waveform have been employed for classification of transformer impulse faults. Experimental results obtained for a 3 MVA transformer and simulation results obtained for 3 MVA, 5 MVA and 7 MVA transformers are presented to illustrate the ability of this approach to classify insulation failures. The results indicate that this new approach possesses reasonable abilities for waveform pattern discrimination.
Terminating the trellis was considered essential to lower the bit error probability in a turbo coded system. When a sliding window algorithm is used, this issue becomes even more important. It is shown that trellis te...
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Terminating the trellis was considered essential to lower the bit error probability in a turbo coded system. When a sliding window algorithm is used, this issue becomes even more important. It is shown that trellis termination can be completely ignored by using an interleaver that takes into account the particular window size of the sliding window algorithm.
The technique of Knowlege Discovery in Databases (KDD) to learn valuable knowledge hidden in network alarm databases is introduced. To get such knowledge, we propose an efficient method based on slidingwindows (named...
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The technique of Knowlege Discovery in Databases (KDD) to learn valuable knowledge hidden in network alarm databases is introduced. To get such knowledge, we propose an efficient method based on slidingwindows (named as Slidwin) to discover different episode rules from time squential alarm data. The experimental results show that given different thresholds parameters, large amount of different rules could be discovered quickly.
Because of non-negligible ISI due to the Gaussian filter and delay spread in the GSM system, an equalizer is required. In this letter, a joint slidingwindow channel estimation and timing adjustment method is proposed...
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Because of non-negligible ISI due to the Gaussian filter and delay spread in the GSM system, an equalizer is required. In this letter, a joint slidingwindow channel estimation and timing adjustment method is proposed fur maximum likelihood sequence equalizer. And also a smoothing algorithm is presented in order to improve the equalizer performance. This smoothing scheme utilizes a variant of LMS algorithm to tune the channel coefficient estimates. Simulation results show that the proposed scheme is adequate for channel estimation of the adaptive equalizer.
This paper examines the problem of video;transport over ATM networks using knowledge of both video system design and broadband networks, The following issues are addressed: video system delay caused by internal buffer...
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This paper examines the problem of video;transport over ATM networks using knowledge of both video system design and broadband networks, The following issues are addressed: video system delay caused by internal buffering, traffic descriptors (TD) for video, and call admission, We find that while different video sequences require different TD parameters, the following trends hold for all sequences examined, First, increasing the delay in the video system decreases the necessary peak rate and significantly increases the number of calls that can be carried by the network, Second;as ah operational traffic descriptor for video, the leaky-bucket algorithm appears to be superior to the sliding-windowalgorithm, And finally, with a delay in the video system, the statistical multiplexing gain from VER over CBR video is upper bounded by roughly a factor of four, and to obtain a gain of about 2.0 can require the operational traffic descriptor to have a window or bucket size on the order of a thousand cells. We briefly discuss how increasing the complexity of the video system may enable the size of the bucket or window to be reduced.
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