In a preemptive priority based RTOS, priority inversion problem is among the major sources of deadline violations. Priority inheritance protocol is one of the approaches to reduce priority inversion. Unfortunately, RTOS like uC/OS can’t support priority inheritance protocol since it does not allow kernel to have multiple tasks at the same priority. Although it has different ways to avoid priority inversion such as priority ceiling protocol, developers still have some difficulties in programming real time applications with it. In this paper, we redesign the uC/OS kernel to provide the ability to support round robin scheduling and implement priority inheritance semaphore on the modified kernel. As result, we port new kernel with priority inheritance semaphore to evaluation board, and evaluate the execution time of each of the kernel service as well as verify the operations of our implementation.
標簽： priority preemptive inversion problem
上傳時間： 2015-12-14
上傳用戶：氣溫達上千萬的
We present a particle filter construction for a system that exhibits time-scale separation. The separation of time-scales allows two simplifications that we exploit: i) The use of the averaging principle for the dimensional reduction of the system needed to solve for each particle and ii) the factorization of the transition probability which allows the Rao-Blackwellization of the filtering step. Both simplifications can be implemented using the coarse projective integration framework. The resulting particle filter is faster and has smaller variance than the particle filter based on the original system. The convergence of the new particle filter to the analytical filter for the original system is proved and some numerical results are provided.
標簽： construction separation time-scale particle
上傳時間： 2016-01-02
上傳用戶：fhzm5658
杭電 ACM 1002 I have a very simple problem for you. Given two integers A and B, your job is to calculate the Sum of A + B.
標簽： integers problem calcul simple
上傳時間： 2014-01-12
上傳用戶：dave520l
Free open-source disk encryption software for Windows Vista/XP, Mac OS X, and Linux Main Features: * Creates a virtual encrypted disk within a file and mounts it as a real disk. * Encrypts an entire partition or storage device such as USB flash drive or hard drive. * Encrypts a partition or drive where Windows is installed (pre-boot authentication). * Encryption is automatic, real-time (on-the-fly) and transparent. * Provides two levels of plausible deniability, in case an adversary forces you to reveal the password: 1) Hidden volume (steganography) and hidden operating system. 2) No TrueCrypt volume can be identified (volumes cannot be distinguished from random data). * Encryption algorithms: AES-256, Serpent, and Twofish. Mode of operation: XTS. Further information regarding features of the software may be found in the:http://www.truecrypt.org/
標簽： open-source encryption Features software
上傳時間： 2013-12-20
上傳用戶：123啊
北京航空航天大學出版社，深入淺出ARM7--LPC213x214x下冊，周立功等編著。本書全面介紹了以LPC213x/LPC214x兩個系列ARM芯片為硬件平臺的各種應用開發，詳細分析了嵌入式實時操作系統μC/OS-II在ARM7上的移植和應用。第101-180頁。
上傳時間： 2013-06-11
上傳用戶：tianjinfan
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
上傳時間： 2013-10-23
上傳用戶：copu
This a Bayesian ICA algorithm for the linear instantaneous mixing model with additive Gaussian noise [1]. The inference problem is solved by ML-II, i.e. the sources are found by integration over the source posterior and the noise covariance and mixing matrix are found by maximization of the marginal likelihood [1]. The sufficient statistics are estimated by either variational mean field theory with the linear response correction or by adaptive TAP mean field theory [2,3]. The mean field equations are solved by a belief propagation method [4] or sequential iteration. The computational complexity is N M^3, where N is the number of time samples and M the number of sources.
標簽： instantaneous algorithm Bayesian Gaussian
上傳時間： 2013-12-19
上傳用戶：jjj0202
這個是Uc/OS－II的中文書，對uc/OS-II進行開發比較有幫助的
上傳時間： 2013-11-29
上傳用戶：gaojiao1999
The government of a small but important country has decided that the alphabet needs to be streamlined and reordered. Uppercase letters will be eliminated. They will issue a royal decree in the form of a String of B and A characters. The first character in the decree specifies whether a must come ( B )Before b in the new alphabet or ( A )After b . The second character determines the relative placement of b and c , etc. So, for example, "BAA" means that a must come Before b , b must come After c , and c must come After d . Any letters beyond these requirements are to be excluded, so if the decree specifies k comparisons then the new alphabet will contain the first k+1 lowercase letters of the current alphabet. Create a class Alphabet that contains the method choices that takes the decree as input and returns the number of possible new alphabets that conform to the decree. If more than 1,000,000,000 are possible, return -1. Definition
標簽： government streamline important alphabet
上傳時間： 2015-06-09
上傳用戶：weixiao99
MISRA (The Motor Industry Software Reliability Association 汽車工業軟件可靠性聯會) 是位于英國的一個跨國汽車工業協會，其成員包括了大部分歐美汽車生產商。其核心使命是為汽車工業提供服務和協助，幫助廠方開發安全的、高可靠性的嵌入式軟件。這個組織最出名的成果是所謂的MISRA C Coding Standard，這一標準中包括了127條C語言編碼標準，通常認為，如果能夠完全遵守這些標準，則你的C代碼是易讀、可靠、可移植和易于維護的。最近很多嵌入式開發者都以MISRA C來衡量自己的編碼風格，比如著名的uC/OS-II就得意地宣稱自己99％遵守MISRA標準。而《嵌入式開發雜志》也專門載文號召大家學習。編碼規范通常是一個公司自定的“土政策”，居然有人去做標準，而且還得到廣泛的認可，這不禁引起我強烈的興趣。可惜這份標準的文本需要花錢去買，而且短短幾十頁，要價非常昂貴。MISRA在網上公布了一些文檔，其中有關于MISRA C Coding Standard的Clarification報告，從中間你可以大致猜到MISRA標準本身是什么。
標簽： Association Reliability Industry Software
上傳時間： 2013-12-27
上傳用戶：wangzhen1990
