A hierarchical test methodology for systems on chip

We present a hierarchical test methodology for testing a SOC with heterogeneous cores, including the 1149.1-wrapped, P1500-wrapped, and BIST memory cores. We propose an 1149.1-based hierarchical test manager that also provides P1500 test control signals. This scheme includes a memory BIST interface, providing both serial and parallel access ports for BIST circuits. Our approach offers low area and pin overhead, and high flexibility     

双重分离全自动控制空气分离器工作过程分析

讨论分析双重分离全自动控制空气分离器的工作过程及影响因素。     

Thin-film reactions during diffusion soldering of Cu/Ti/Si and Au/Cu/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> with Sn interlayers

The multilayer thin-film systems of Cu/Ti/Si and Au/Cu/Al₂O₃ were diffusion-soldered at temperatures between 250°C and 400°C by inserting a Sn thin-film interlayer. Experimental results showed that a double layer of intermetallic compounds (IMCs) η-(Cu_0.99Au_0.01)₆Sn₅/δ-(Au_0.87Cu_0.13)Sn was formed at the interface. Kinetics analyses revealed that the growth of intermetallics was diffusion-controlled. The activation energies as calculated from Arrhenius plots of the growth rate constants for (Cu_0.99Au_0.01)₆Sn₅ and (Au_0.87Cu_0.13)Sn are 16.9 kJ/mol and 53.7 kJ/mol, respectively. Finally, a satisfactory tensile strength of 132 kg/cm² could be attained under the bonding condition of 300°C for 20 min.     

Designing a binary controller to enhance end-to-end congestion control

Active queue management (AQM) is proposed to enhance end-to-end congestion control through purposefully dropping packets in the intermediate nodes. In this letter, a novel packet dropping mechanism is developed through designing a binary controller applying the robust control theory. The new mechanism can simplify the manipulation on the AQM router so as to be helpful for implementing the high performance router. The numerical simulation results show that the binary controller can satisfy with the technical requirements for AQM     

Mechanical strength of Sn-3.5Ag-based solders and related bondings

The tensile strengths of bulk solders and joint couples of Sn-3.5Ag-0.5Cu, Sn-3.5Ag-0.07Ni, and Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge solders and the shear strengths of ball grid array (BGA) specimens, solder-ball-attached Cu/Ni/Au metallized substrates were investigated. The tensile strength of the bulk is degraded by thermal aging. The Ni-containing solder exhibits lower tensile strength than Sn-3.5Ag-0.5Cu after thermal aging. However, the Ni-containing solder joints show greater tensile strength than the Cu/Sn-3.5Ag-0.5Cu/Cu joint. Fracture of the solder joint occurs between the intermetallic compound (IMC) and the solder. The shear strength and fracture mechanism of BGA specimens are the same regardless of solder composition.     

Hiding data in multitone images for data communications

Two novel data-hiding schemes for secure data communications are presented. These two schemes perform on the pixel differences between the original (host) image and the decompressed image, which is inspired from Wu's and Chao's methods. The first scheme, referred to as 'scheme-1', utilises the differences between two similar images and then embeds the secret data into the different parts. In the embedding process, two auxiliary techniques, zero-replacement and complement-bit, will also be incorporated. In addition, to enhance the hiding efficiency of scheme-1, the authors have followed the bit-plane hiding strategy and created scheme-2. The proposed schemes have two advantages. First, the error distortion can be measured before the hiding process begins. Second, there is no complex computation, which means the hiding process can be executed very efficiently. The experimental results show that the two proposed schemes can achieve better image quality than other data-hiding schemes. At the same time, the new schemes can also satisfy the three basic requirements a data hiding scheme should live up to: invisibility, capacity and data security.     

Access algorithm for packetized wireless transmission in thepresence of cochannel interference

Packetized access has some potential advantages over conventional circuit-switched-based access methods because several signal sources can share the same radio channel using statistical multiplexing. We consider radio resource assignment algorithms for packetized access based on the packet-reservation multiple-access (PRMA) protocol in the presence of cochannel interference. The statistical multiplexing gain of packet access is limited by frequency reuse, especially when the reuse factor is low or duality requirement is high. We propose a fuzzy logic-based adaptive medium-access control (MAC) algorithm to improve packet-access efficiency. Computer simulations based on the example of packetized voice have confirmed that the proposed packet-access protocol can support a higher number of active users per radio port than that supported by random slot assignment     

Unsupervised Learning for Solving RSS Hardware Variance Problem in WiFi Localization

Hardware variance can significantly degrade the positional accuracy of RSS-based WiFi localization systems. Although manual adjustment can reduce positional error, this solution is not scalable as the number of new WiFi devices increases. We propose an unsupervised learning method to automatically solve the hardware variance problem in WiFi localization. This method was designed and implemented in a working WiFi positioning system and evaluated using different WiFi devices with diverse RSS signal patterns. Experimental results demonstrate that the proposed learning method improves positional accuracy within 100 s of learning time.     

Fast Duplicate Address Detection for Seamless Inter-Domain Handoff in All-IPv6 Mobile Networks

In All-IP networks, each computer or communication equipment needs an IP address. To supply enough IP addresses, the new Internet protocol IPv6 will be used in next generation mobile communication. Although IPv6 improves the existing Internet protocol (IPv4), Duplicate Address Detection (DAD) mechanism may consume resources and suffer from long delay. DAD is used to make sure whether the IP address is unique or not. When a mobile node performs an inter-domain handoff, it will first generate a new IP and perform a DAD procedure. The DAD procedure not only wastes time but also increases the signaling load on Internet. In this paper, we propose a new DAD mechanism to speed up the DAD procedure. We create a DAD table in access or mobility routers in All-IP networks and record all IP addresses of the area. When a new IP address needs to perform DAD, it can just search in the DAD table to confirm the uniqueness of the address. Furthermore, we propose a new method, Fast Duplicate Address Detection (Fast DAD), to reduce data search time. Simulation results show that our method outperforms the existing DAD methods.     

Diversity Combining and Equalization with TCM for Wireless Communications

This paper presents an equalization structure in which antennadiversity, adaptive decision feedback equalization (DFE), interleavingand trellis-coded modulation (TCM) can be effectively combined to combatboth ISI and cochannel interference in cellular mobile radioenvironments. The feedback filter of the DFE can use either tentative orfinal decision symbols of the TCM Viterbi decoding to cancel tail ISIwith the square root Kalman algorithm. A performance bound on theaverage pairwise error probability for TCM under perfect interleavingand equalization is obtained by analysis. Some simulation results whichillustrate the potential of the proposed system will also be given. Inparticular, a performance comparison between the proposed method anduncoded QPSK modulation will be undertaken.