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The microstructure and mechanical behavior of Sn-Ag-Cu (SAC) soldering alloys can change significantly over time when exposed to isothermal aging and in-situ current stress. Electronics assemblies built with SAC solder joints are exposed to elevated ambient temperatures and relatively high current densities for prolonged periods of time. Therefore it is important to understand the impact of these...
In this study, a comprehensive set of tests were performed on test vehicles with different package types, sizes, pitches, and solder joints metallurgies. Accelerated Thermal Cycling (ATC) testing was performed using four different thermal cycling profiles: 0–100 °C, −40–125 °C, −55–125 °C, and −60–150 °C. Data from the tests were analyzed for failure mode and failure rate using Weibull statistics,...
Chip-scale package (CSP) is commonly seen on high density boards as it minimizes the foot print while packed more functionality into one component. Board level reliability concern over CSPs is that finer pitch limits the solder ball size attached and the stencil thickness used in assembly which leads to much smaller joint volume and standoff while larger die-to-package ratio typically means higher...
Sn-Ag-Cu (SAC) solder alloys, such as Sn-3.0Ag-0.5 Cu (SAC305) are the popular choices of lead-free solders replacing SnPb solders. However, SAC solders are more brittle in nature due to high stiffness and excessive intermetallic compounds growth at the solder joint to pad interface. This leads to higher risks in solder joints failures. Memory module type lead-free BGA packages are constantly under...
This paper reports the experimental and theoretical exploration of the fracture mechanism active in BGA lead-free solder assemblies under high speed shear fatigue test conditions. Our investigation finds that, contrary to common assumption, the crack growth in shear fatigue is not governed by shear stress but more by crack opening stress. Our theoretical analysis indicates that fracture by crack opening...
Thermally cycled PBGA packages with a full array of 196 solder joints after various pre-conditions are examined to observe the microstructure evolution of Sn-Ag-Cu solder joints during aging and thermal cycling, focusing on Sn grain orientation. Each PBGA package was polished to obtain plan view cross sections of every solder joint, and characterized using both Polarized Optical microscopy and Orientation...
Vehicular Ad-hoc NETworks (VANETs) adopting Dedicated Short-Range Communications (DSRCs) have emerged as a preferred choice of network design for the Intelligent Transportation System (ITS). A possible application of the ITS is to disseminate emergency messages by multihop broadcast. Due to the high density and high mobility of vehicles, it is difficult to design an efficient broadcast protocol for...
For developing the intuitionistic fuzzy aggregation operators to handle intuitionistic fuzzy multi-criteria fuzzy decision making problems, the most important issue is how to find an addition-invariant partial order to construct an ordered addition monoid of intuitionistic fuzzy values. In this paper, we point out that Atanassov's order is not a totally partial order, and the popular partial order,...
In this paper, a generalized L-measure, denoted LG-measure, is proposed. This new measure is proved that it is of closed form with infinitely many solutions, and can be considered as an extension of the three well known measures, additive measure, λ-measure and P-measure, respectively. Furthermore, it is a completed multivalent fuzzy measure, and not only including the smallest fuzzy measure, P-measure,...
In the past, although mobile devices were equipped with multiple radio interfaces, for the sake of power saving, only one was activated for data transmission. The idea of concurrent transmission via multiple radio interfaces has not been seriously studied. However, nowadays, power consumption no longer is a problem in many application scenarios, e.g. VANETs. In this work, we investigate the performance...
The success of P2P file sharing systems inspired the development of P2P streaming systems for delivering online multimedia service in the last few years. The capacity of P2P streaming systems, i.e., how many peers can be concurrently serviced by the system, depends on system configurations including network bandwidth, overlay network formation, QoS constraints, membership management, peer selection,...
Software Radio (SR) is an emerging paradigm of the wireless communication system design due to its flexibility and adaptability. However, the implementation of SR platform is always challenging, especially for high date rate transmission such as up to 1Gbps. Although general-purpose processor(GPP) based SR platform can take full advantages of Software Radio, the performance is often limited due to...
For developing the intuitionistic fuzzy aggregation operators to handle intuitionistic fuzzy multi-criteria fuzzy decision making problems, two popular partial orders are used, one is Atanassov's order and the other is Xu's order. Both of them disregard the following important condition, “a feasible partial order must be not only a totally partial order but also an operation-invariant partial order”...
The well known normalized monotone measures, ??-measure and P-measure, have only one formulaic solution. A multivalent normalized monotone measure with infinitely many solutions was proposed by our previous work, called L-measure, but L-measure is not a completed measure. And then, a completed measure with more many solutions than L-measure, called completed L-measure, was proposed by our next previous...
In two dimensional simulation, we found that Raleigh-Taylor (R-T) instability of accelerating thin foil, plays a significant role in preventing the coherent acceleration of the double layer as a whole, particularly the nonlinear stage of its development. The usual nonlinear development of R-T instability generates fingers of high and low densities at the most unstable mode with wavelength comparable...
Establishing a good algorithm for predicting temperature of thermostable proteins is an important issue. In this study, an improved thermostable proteins prediction method using Hurst exponent and Choquet integral regression model based on completed L-measure is proposed. The main idea of this method is to integrate the physicochemical properties, fractal property and Choquet integral regression model...
In this paper, we propose a localized network-coding-based packet forwarding protocol for wireless networks, called Opportunistic Asynchronous Information dissemination (OASIS), based on COPE. OASIS not only inherents two features from COPE, opportunistic listening and opportunistic coding, but also introduces a new one, opportunistic information dissemination, which aggressively encodes as many packets...
The well known fuzzy measures, ??-measure and P-measure, both of them have only one formulaic solution. A multivalent fuzzy measure with infinitely many solutions was proposed by our previous work, called L-measure, but it is not a completed measure. After that, an improved completed measure with more many solutions than L-measure, called complete L-measure, was also proposed by the author. In this...
The SAR remote sensing images are interfered by noises during the detection and transmission, a method based on wavelet packet and level dependent adaptive threshold is proposed in this paper. By using this method, the SAR images can be decomposed in a more elaborate method compared to the traditional wavelet transform, and the noises in the SAR images are eliminated by the adaptive threshold method...
The well known fuzzy measures, ??-measure and P-measure, have only one formulaic solution. An multivalent fuzzy measure with infinitely many solutions of closed form based on P-measure was proposed by our previous work, called L-measure, In this paper, A further improved fuzzy measure, called extensional L-measure, is proposed. This new fuzzy measure is proved that it is not only an extension of L-measure...
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