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1.
Machine Learning - In survival analysis, estimating the failure time distribution is an important and difficult task, since usually the data is subject to censoring. Specifically, in this paper we... 相似文献
2.
A group of people taking pictures of a dynamic event with their mobile phones is a popular sight. The set of still images obtained this way is rich in dynamic content but lacks accurate temporal information. We propose a method for photo-sequencing—temporally ordering a set of still images taken asynchronously by a set of uncalibrated cameras. Photo-sequencing is an essential tool in analyzing (or visualizing) a dynamic scene captured by still images. The first step of the method detects sets of corresponding static and dynamic feature points across images. The static features are used to determine the epipolar geometry between pairs of images, and each dynamic feature votes for the temporal order of the images in which it appears. The partial orders provided by the dynamic features are not necessarily consistent, and we use rank aggregation to combine them into a globally consistent temporal order of images. We demonstrate successful photo-sequencing on several challenging collections of images taken using a number of mobile phones. 相似文献
3.
DNA‐Metalization: Synthesis and Properties of Novel Silver‐Containing DNA Molecules (Adv. Mater. 24/2016)
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4.
Tracking in a Dense Crowd Using Multiple Cameras 总被引:1,自引:0,他引:1
Tracking people in a dense crowd is a challenging problem for a single camera tracker due to occlusions and extensive motion that make human segmentation difficult. In this paper we suggest a method for simultaneously tracking all the people in a densely crowded scene using a set of cameras with overlapping fields of view. To overcome occlusions, the cameras are placed at a high elevation and only people’s heads are tracked. Head detection is still difficult since each foreground region may consist of multiple subjects. By combining data from several views, height information is extracted and used for head segmentation. The head tops, which are regarded as 2D patches at various heights, are detected by applying intensity correlation to aligned frames from the different cameras. The detected head tops are then tracked using common assumptions on motion direction and velocity. The method was tested on sequences in indoor and outdoor environments under challenging illumination conditions. It was successful in tracking up to 21 people walking in a small area (2.5 people per m2), in spite of severe and persistent occlusions. 相似文献
5.
Moses Yael Shimshoni Ilan 《IEEE transactions on pattern analysis and machine intelligence》2009,31(7):1310-1324
We present a new method for recovering the 3D shape of a featureless smooth surface from three or more calibrated images illuminated by different light sources (three of them are independent). This method is unique in its ability to handle images taken from unconstrained perspective viewpoints and unconstrained illumination directions. The correspondence between such images is hard to compute and no other known method can handle this problem locally from a small number of images. Our method combines geometric and photometric information in order to recover dense correspondence between the images and accurately computes the 3D shape. Only a single pass starting at one point and local computation are used. This is in contrast to methods that use the occluding contours recovered from many images to initialize and constrain an optimization process. The output of our method can be used to initialize such processes. In the special case of fixed viewpoint, the proposed method becomes a new perspective photometric stereo algorithm. Nevertheless, the introduction of the multiview setup, self-occlusions, and regions close to the occluding boundaries are better handled, and the method is more robust to noise than photometric stereo. Experimental results are presented for simulated and real images. 相似文献
6.
An in-depth evaluation of the usability and situation awareness performance of different displays and destination controls of robots are presented. In two experiments we evaluate the way information is presented to the operator and assess different means for controlling the robot. Our study compares three types of displays: a “blocks” display, a HUD (head-up display), and a radar display, and two types of controls: touch screen and hand gestures. The HUD demonstrated better performance when compared to the blocks display and was perceived to have greater usability compared to the radar display. The HUD was also found to be more useful when the operation of the robot was more difficult, i.e., when using the hand-gesture method. The experiments also pointed to the importance of using a wide viewing angle to minimize distortion and for easier coping with the difficulties of locating objects in the field of view margins. The touch screen was found to be superior in terms of both objective performance and its perceived usability. No differences were found between the displays and the controllers in terms of situation awareness. This research sheds light on the preferred display type and controlling method for operating robots from a distance, making it easier to cope with the challenges of operating such systems. 相似文献
7.
The CALPHAD method can be applied as a tool for both alloy development and process guideline determination. In this study, two Mg alloys were designed, their process parameters derived and, using the CALPHAD method, the final results simulated. These results were later confirmed using tangible experimental methods. It was found that γ- Mg17Al12 precipitates along the grain boundaries (GB), Mg2Sn forms both along the GB and as fine precipitates in the α-Mg matrix and the addition of Ce mishmetal (MM) leads to the formation of elongated Al- rare earth (RE) precipitates along the GB. The microstructural stability at 200 °C is high, showing no decrease in microhardness for 32 days. It is shown that the CALPHAD method considerably reduces the effort of alloy design and that the reliability of the results is high. 相似文献
8.
J Connor R Bannerji S Saito W Heston W Fair E Gilboa 《Canadian Metallurgical Quarterly》1993,177(4):1127-1134
This study explored the use of interleukin 2 (IL-2) and interferon gamma (IFN-gamma) gene-modified tumor cells as cellular vaccines for the treatment of bladder cancer. The mouse MBT-2 tumor used is an excellent model for human bladder cancer. This carcinogen-induced tumor of bladder origin resembles human bladder cancer in its etiology and histology, and responds to treatment in a manner similar to its human counterpart. Using retroviral vectors, the human IL-2 and mouse IFN-gamma genes were introduced and expressed in MBT-2 cells. The tumor-forming capacity of the cytokine gene-modified MBT-2 cells was significantly impaired, since no tumors formed in mice injected intradermally with either IL-2- or IFN-gamma-secreting cells, using cell doses far exceeding the minimal tumorigenic dose of parental MBT-2 cells. Furthermore, mice that rejected the IL-2- or IFN-gamma-secreting tumor cells became highly resistant to a subsequent challenge with parental MBT-2 cells, but not to 38C13 cells, a B cell lymphoma of the same genetic background. To approximate the conditions as closely as possible to the conditions prevailing in the cancer patient, inactivated cytokine-secreting cells were used to treat animals bearing tumors established by orthotopic implantation of MBT-2 cells into the bladder wall of the animal. Treatment of mice carrying a significant tumor burden with IL-2-secreting MBT-2 cells had a significant inhibitory effect on tumor progression with extended survival. Moreover, in 60% of the mice the tumor regressed completely and the animals remained alive and free of detectable tumor for the duration of the observation period. Treatment of tumor-bearing animals with IL-2-secreting MBT-2 cells was superior to the use of cisplatin, a chemotherapeutic agent used in the treatment of bladder cancer. The therapeutic effect of IFN-gamma-secreting cells was minimal and treatment with unmodified MBT-2 cells had no effect on tumor growth or survival, showing that the parental MBT-2 cells were nonimmunogenic in this experimental setting. Most importantly, mice that exhibited complete tumor regression after treatment with IL-2-secreting MBT-2 cells became resistant to a subsequent challenge with a highly tumorigenic dose of parental MBT-2 cells, indicating that long-term immunological memory was established in the "cured" mice. 相似文献
9.
10.
The weak form of the Efficient Market Hypothesis (EMH) states that current market price reflects fully the information from past prices and rules out prediction based on price data alone. No recent test of time series of stock returns rejects this weak-form hypothesis. This research offers another test of the weak form of the EHM that leads to different conclusions for some time series.The stochastic complexity of a time series is a measure of the number of bits needed to represent and reproduce the information in the time series. In an efficient market, compression of the time series is not possible, because there are no patterns and the stochastic complexity is high. In this research, Rissanen's context tree algorithm is used to identify recurring patterns in the data, and use them for compression. The weak form of the EMH is tested for 13 international stock indices and for all the stocks that comprise the Tel-Aviv 25 index (TA25), using sliding windows of 50, 75, and 100 consecutive daily returns. Statistically significant compression is detected in ten of the international stock index series. In the aggregate, 60% to 84% of the TA25 stocks tested demonstrate compressibility beyond randomness. This indicates potential market inefficiency. 相似文献