The Internet of Things is considered to be the next big opportunity, and challenge, for the Internet engineering community, users of technology, companies and society as a whole. It involves connecting embedded devices such as sensors, home appliances, weather stations and even toys to Internet Protocol (IP) based networks. The number of IP-enabled embedded devices is increasing rapidly, and although hard to estimate, will surely outnumber the number of personal computers (PCs) and servers in the future. With the advances made over the past decade in microcontroller,low-power radio, battery and microelectronic technology, the trend in the industry is for smart embedded devices (called smart objects) to become IP-enabled, and an integral part of the latest services on the Internet. These services are no longer cyber, just including data created by humans, but are to become very connected to the physical world around us by including sensor data, the monitoring and control of machines, and other kinds of physical context. We call this latest frontier of the Internet, consisting of wireless low-power embedded devices, the Wireless Embedded Internet. Applications that this new frontier of the Internet enable are critical to the sustainability, efficiency and safety of society and include home and building automation, healthcare, energy efficiency, smart grids and environmental monitoring to name just a few.
標(biāo)簽： Embedded Internet Wireless 6LoWPAN The
上傳時(shí)間： 2020-05-26
上傳用戶：shancjb
The field of digital communication has evolved rapidly in the past few decades, with commercial applications proliferating in wireline communi- cation networks (e.g., digital subscriber loop, cable, fiber optics), wireless communication (e.g., cell phones and wireless local area networks), and stor- age media (e.g., compact discs, hard drives). The typical undergraduate and graduate student is drawn to the field because of these applications, but is often intimidated by the mathematical background necessary to understand communication theory.
標(biāo)簽： Communication Fundamentals Digital of
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
FPGA HArd Ethercat Master
標(biāo)簽： Ethercat master FPGA
上傳時(shí)間： 2020-05-30
上傳用戶：q8360428
The ever-increasing demand for private and sensitive data transmission over wireless net- works has made security a crucial concern in the current and future large-scale, dynamic, and heterogeneous wireless communication systems. To address this challenge, computer scientists and engineers have tried hard to continuously come up with improved crypto- graphic algorithms. But typically we do not need to wait too long to find an efficient way to crack these algorithms. With the rapid progress of computational devices, the current cryptographic methods are already becoming more unreliable. In recent years, wireless re- searchers have sought a new security paradigm termed physical layer security. Unlike the traditional cryptographic approach which ignores the effect of the wireless medium, physi- cal layer security exploits the important characteristics of wireless channel, such as fading, interference, and noise, for improving the communication security against eavesdropping attacks. This new security paradigm is expected to complement and significantly increase the overall communication security of future wireless networks.
標(biāo)簽： Communications Physical Security Wireless Layer in
上傳時(shí)間： 2020-05-31
上傳用戶：shancjb
This book was born from the perception that there is much more to spectrum use and sharing than one sees reflected in publications, whether academic, commercial or political. the former – in good research style – tend towards reductionism and concentrate on specific, detailed aspects. commercial publications tend to empha- size the positive aspects and they tend to put promise above practice. Given the ever increasing pace of technology development and recent successes of new wireless technologies, some pundits predict large-scale spectrum scarcity, potentially lead- ing to economic catastrophe. Although economic theory has a hard time explaining recent events that shook the world economy, the notion of spectrum scarcity is intui- tively acceptable, even if not correct or immediately relevant.
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
The serious study of the practice of how to determine the appropriate content of a specification is a seldom-appreciated pastime. Those who have the responsibility to design a product would prefer a greater degree of freedom than permitted by the con- tent of a specification. Many of those who would manage those who would design a product would prefer to allocate all of the project funding and schedule to what they consider more productive labor. These are the attitudes, of course, that doom a project to defeat but they are hard to counter no matter how many times repeated by design engineers and managers. A system engineer who has survived a few of these experiences over a long career may retire and forget the past but we have an endur- ing obligation to work toward changing these attitudes while trying to offer younger system engineers a pathway toward a more sure success in requirements analysis and specification publishing.
標(biāo)簽： Requirements Analysis System
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Machine learning is a broad and fascinating field. Even today, machine learning technology runs a substantial part of your life, often without you knowing it. Any plausible approach to artifi- cial intelligence must involve learning, at some level, if for no other reason than it’s hard to call a system intelligent if it cannot learn. Machine learning is also fascinating in its own right for the philo- sophical questions it raises about what it means to learn and succeed at tasks.
標(biāo)簽： Learning Machine Course in
上傳時(shí)間： 2020-06-10
上傳用戶：shancjb
全志A20核心板配套開(kāi)發(fā)底板Cadence原理圖+ Pads2005格式PCB文件+轉(zhuǎn)換后的AD格式原理圖PCB文件：A20_DVK1_BASE_V16_Altium_Designer15.PcbDocA20_DVK1_BASE_V16_BOM_20151015.xlsxA20_DVK1_BASE_V16_Gerber制板文件.rarA20_DVK1_BASE_V16_PADS2005_PCB30.pcbA20_DVK1_BASE_V16_PADS2005_PCB_ASCII.PcbDocA20_DVK1_BASE_V16_PADS9.5.pcba20_dvk1_base_v16_SCH_20151015.pdfA20_DVK1_BASE_V16_元件位置查找圖_20151102.pdfA20_DVK1_BASE_V16_原理圖_OrCAD16.5.DSNA20_DVK1_BASE_V16_導(dǎo)出到AD格式的原理圖和PCBA20_DVK1_BASE_V16_導(dǎo)出到AD格式的原理圖和PCB.rarA20_DVK1_BASE_V16_頂層元件編號(hào)絲印圖_20151102.pdfA20_DVK1_BASE_V16_頂層元件規(guī)格絲印圖_20151102.pdf主要器件如下：Library Component Count : 58Name Description----------------------------------------------------------------------------------------------------ANTBATTERY_1BEAD CAPCAP NP 貼片電容,Y5V,6.3V,2.2uF,+80%-20%,0603CAP NP_2_Dup1 X5RCAP NP_Dup2 0402 1uF X5R 6.3V +/-10%CAP NP_Dup3 0402 1uF X5R 6.3V +/-10%CAPACITOR CAPACITOR POLCON1 CON12 CON3 CON4 CON50 CON6CON6A CONNECTOR45X4 C_Generic DB15-VGA_0 DIODE DIODE DUAL SERIESFM25CL64 FR9886SPGTR FUSEHOLDER_0 HDMI19_PLUG HEADER 2 INDUCTOR/SMINDUCTOR_4 C4K-2.5HINDUCTOR_Dup2 INDUCTOR_Dup3 IRM-2638LED_0M93C46_0 MINI USB-B_6 MODULE_CAM_PA0505 PH163539 PLAUSB-AF5P-WSMT_0 PUSHBUTTON_TSKB-2L_0PowerJACK R1 0805 R1_0805 RES2X4RESISTOR RESISTOR_Dup1 RESISTOR_Dup2 RESISTOR_V RJ45_8PGR_Generic S9013SMD_Dup2 SD_MMC_CARD2_0 TP_5 TestPoint_3TitleBlock_Gongjun USBPORT2 USB_WIFI_0 XC6204VZ_3 LDO 3.3V 300mA( SOT-25 )rRClamp0524P
上傳時(shí)間： 2021-11-08
上傳用戶：
移動(dòng)機(jī)器人路徑規(guī)劃尤其是未知環(huán)境下機(jī)器人路徑規(guī)劃是機(jī)器人技術(shù)中的一個(gè)重要研究領(lǐng)域，得到了很多研究者的關(guān)注，并取得了一系列重要成果。目前已存在許多用來(lái)解決該問(wèn)題的優(yōu)化算法，但是此類(lèi)問(wèn)題屬于N-Hard問(wèn)題，尋求更佳的算法就成為該領(lǐng)域的一個(gè)研究熱點(diǎn)。為此，根據(jù)機(jī)器人路徑規(guī)劃算法的研究現(xiàn)狀和向智能化，仿生化發(fā)展的趨勢(shì)，研究了一種基于圖的機(jī)器人路徑規(guī)劃螞蟻優(yōu)化算法。算法首先用柵格法對(duì)機(jī)器人的工作空間進(jìn)行建模，并用一個(gè)狀態(tài)矩陣表示其狀態(tài)，由此構(gòu)造出一個(gè)連通圖，由一組螞蟻在圖上模擬螞蟻的覓食行為，從而得到避碰的優(yōu)化路徑。最后，借鑒分枝隨機(jī)過(guò)程和生滅過(guò)程的理論知識(shí)，用概率的方法從理論上對(duì)該算法的收斂性進(jìn)行了分析，在此基礎(chǔ)上，結(jié)合計(jì)算機(jī)仿真結(jié)果，證實(shí)了本文提出的算法的有效性和收斂性。迄今為止，對(duì)于未知環(huán)境下機(jī)器人路徑規(guī)劃，人們已經(jīng)探索出了許多有效的求解方法諸如虛擬力場(chǎng)法、基于學(xué)習(xí)或Q學(xué)習(xí)的規(guī)劃方法、滾動(dòng)窗口規(guī)劃方法、非啟發(fā)式方法及各類(lèi)定位、導(dǎo)航方法等等。近年來(lái)，不少學(xué)者用改進(jìn)的遺傳算法、神經(jīng)網(wǎng)絡(luò)、隨機(jī)樹(shù)、蟻群算法等方法對(duì)未知環(huán)境下機(jī)器人路徑進(jìn)行了規(guī)劃?rùn)C(jī)器人路徑規(guī)劃算法向智能化、仿生化發(fā)展是一個(gè)明顯的趨勢(shì).由于已有算法不同程度的存在一定局限性，諸如搜索空間大、算法復(fù)雜、效率不高等，尤其對(duì)于未知環(huán)境，不少路徑規(guī)劃算法的復(fù)雜度較高，甚至無(wú)法求解，根據(jù)日前的研究現(xiàn)狀和不足，本文提出了一種用于解決未知環(huán)境下機(jī)器人路徑規(guī)劃的基于圖的螞蟻算法，理論分析和實(shí)驗(yàn)結(jié)果都證明了本文算法的有效性和收斂性本課題研究的主要內(nèi)容本文在用概格法對(duì)機(jī)器人的工作空間進(jìn)行建模的基礎(chǔ)上，用一個(gè)狀態(tài)矩陣表示其狀態(tài)，由此構(gòu)造一個(gè)連通圖，由一組螞蚊在圖上模擬螞蟻的覓食行為，從而得到避碰的優(yōu)化路徑并借鑒分枝隨機(jī)過(guò)程和生滅過(guò)程的理論知識(shí)用概率的方法從理論上對(duì)該算法的收斂性進(jìn)行了分析，結(jié)合計(jì)算機(jī)仿真，證明了本文算法的有效性和收斂性
標(biāo)簽： 機(jī)器人 路徑規(guī)劃 螞蟻算法
上傳時(shí)間： 2022-03-10
上傳用戶：kingwide
反激式開(kāi)關(guān)電源變壓器設(shè)計(jì)的詳細(xì)步驟85W反激變壓器設(shè)計(jì)的詳細(xì)步驟 1. 確定電源規(guī)格. 1).輸入電壓范圍Vin=90—265Vac; 2).輸出電壓/負(fù)載電流:Vout1=42V/2A, Pout=84W 3).轉(zhuǎn)換的效率=0.80 Pin=84/0.8=105W 2. 工作頻率，匝比, 最低輸入電壓和最大占空比確定. Ｖmos*0.8>Vinmax+n(Vo+Vf)600*0.8>373+n(42+1)得n<2.5Vd*0.8>Vinmax/n+Vo400*0.8>373/n+42得n>1.34 所以n取1.6最低輸入電壓Vinmin=√[(Vacmin√2)* (Vacmin√2)-2Pin(T/2-tc)/Cin=(90√2*90√2-2*105*(20/2-3)/0.00015=80V取:工作頻率fosc=60KHz, 最大占空比Dmax=n(Vo+Vf)/[n(Vo+Vf)+Vinmin]= 1.6(42+1)/[1.6(42+1)+80]=0.45 Ton(max)=1/f*Dmax=0.45/60000=7.5us 3. 變壓器初級(jí)峰值電流的計(jì)算. Iin-avg=1/3Pin/Vinmin=1/3*105/80=0.4AΔIp1=2Iin-avg/D=2*0.4/0.45=1.78AIpk1=Pout/?/Vinmin*D+ΔIp1=84/0.8/80/0.45=2.79A 4. 變壓器初級(jí)電感量的計(jì)算. 由式子Vdc=Lp*dip/dt,得: Lp= Vinmin*Ton(max)/ΔIp1 =80*0.0000075/1.78 =337uH 取Lp=337 uH 5.變壓器鐵芯的選擇. 根據(jù)式子Aw*Ae=Pt*1000000/[2*ko*kc*fosc*Bm*j*?],其中: Pt(標(biāo)稱(chēng)輸出功率)= Pout=84W Ko(窗口的銅填充系數(shù))=0.4 Kc(磁芯填充系數(shù))=1(對(duì)于鐵氧體), 變壓器磁通密度Bm=1500Gs j(電流密度): j=4A/mm2;Aw*Ae=84*1000000/[2*0.4*1*60*103*1500Gs*4*0.80]=0.7cm4 考慮到繞線空間,選擇窗口面積大的磁芯,查表: ER40/45鐵氧體磁芯的有效截面積Ae=1.51cm2 ER40/45的功率容量乘積為 Ap = 3.7cm4 >0.7cm4 故選擇ER40/45鐵氧體磁芯. 6.變壓器初級(jí)匝數(shù) 1).由Np=Vinmin*Ton/[Ae*Bm],得: Np=80*7.5*10n-6/[1.52*10n-4*0.15] =26.31 取 Np =27T 7. 變壓器次級(jí)匝數(shù)的計(jì)算. Ns1(42v)=Np/n=27/1.6=16.875 取Ns1 = 17T Ns2(15v)=(15+1)* Ns1/(42+1)=6.3T 取Ns2 = 7T
標(biāo)簽： 開(kāi)關(guān)電源 變壓器
上傳時(shí)間： 2022-04-15
上傳用戶：
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