Johnson W.H.A.,Behrend College |
Filippini R.,University of Padua
Journal of Engineering and Technology Management - JET-M | Year: 2013
The use of integration practices, both internal (where various functions work together) and external (links with customers and suppliers during development), are espoused in the new product development (NPD) literature. However, empirical findings in the literature suggest adoption of integration practices does not necessarily lead to positive performance. We introduce the concept of integration capabilities to explain the relationship between use of integration practices and NPD performance. We tested a mediation model using data from 141 Japanese and American firms and found that effects of both types of integration on time and product performance were mediated by the integration capabilities developed. We also found differential effects of the type of integration. The findings demonstrate that developing superior integration capabilities are needed for companies to meet and exceed product development expectations in terms of both product and time performance. Simply, a company may utilize integration practices but if it does not utilize them in such a way as to generate real capabilities, the use of integration practices may not lead to positive performance effects. © 2012 Published by Elsevier B.V. All rights reserved.
Caliskan-Demirag O.,Behrend College |
Chen Y.,City University of Hong Kong |
Yang Y.,Zhejiang University
Operations Research | Year: 2012
We consider a stochastic periodic-review inventory control system in which the fixed cost depends on the order quantity. In particular, we investigate the optimal ordering policies under three fixed cost structures. The first structure is motivated by transportation and production contracts and considers two fixed costs: if the order size is within a specified limit C, then the fixed cost is K 1; otherwise, it is K 2, where K 1 ≤ K 2. The second structure contains multiple fixed costs in which the same incremental fixed cost K is incurred for any additional order quantity up to a given identical batch capacity C. In the third structure, in addition to the K incurred as in the previous case, a common fixed cost is charged for any nonzero order size. An example of the former case arises when an order is shipped with a homogeneous fleet of trucks with per-truck fixed costs. A situation in which a fixed administrative cost plus a quantity-dependent trucking cost is incurred for each shipment exemplifies the latter case. For the first cost structure, we separate the analysis according to the conditions (1) K 1 ≤ K 2 ≤ 2K 1 and (2) K 1 ≤ K 2. Under condition (1), we introduce a new concept called C-(K 1,K 2)-convexity, which enables us to almost completely characterize the optimal ordering policy. Under the general condition (2), we utilize a modified notion to provide a partial characterization of the optimal policy and propose a heuristic policy that performs well under a wide variety of model parameters. For the second cost structure, we show that it is optimal to order an integer multiple of the batch capacity to raise the inventory level to a specified range or band of length C, and then to order an additional full or partial batch size depending on the cost function, with no ordering required above the band. We also characterize a similar optimal policy for the third cost structure. Using different techniques, our study extends or redevelops several existing results in the literature. © 2012 INFORMS.
Zhong Y.,Behrend College |
Fang T.,North Carolina State University
International Journal of Heat and Mass Transfer | Year: 2011
Unsteady plane and axisymmetric stagnation flow of an incompressible viscous fluid on the body that moves along the oncoming flow with a time-dependent velocity is studied in this work. Similarity solutions for the full Navier-Stokes equations are obtained and the results of the flow velocity, shear stress and stream lines are reported for both plane two dimensional flow and axisymmetric flow. The results show that the features of the similar boundary flow highly depends on a characteristic parameter β. There exists a critical value βc below which no similarity solution to the flow is found. When βc < β < 0, two solution branches exist and different flow patterns appear for each branch. Flow with monophonically growing velocity, reversed flow and flow with S-shaped velocity are obtained for various values of β. The boundary layer thickness of the plane and axisymmetric flows is tabulated, the streamlines of the flow are demonstrated, and the shear stress over the boundary layer is also discussed. © 2010 Elsevier Ltd. All rights reserved.
Murthy-Bellur D.,Behrend College |
Kazimierczuk M.K.,Wright State University
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2011
This brief introduces an isolated two-switch Zeta dc-dc converter, along with the steady-state analysis and experimentation. The high transistor voltage stress due to the ringing caused by the resonance of the transformer leakage inductance and the transistor output capacitance is a major drawback in the conventional isolated Zeta converter. With the incorporation of an additional transistor and two clamping diodes on the primary side of the transformer of the isolated Zeta converter, an isolated two-transistor Zeta converter is proposed. In the proposed converter, the voltage stress of both transistors is reduced to the dc input voltage V I. Experimental results from a 10-V/30-W 100-kHz laboratory prototype is presented to validate the theoretical analysis. © 2006 IEEE.
Walters E.G.,Behrend College
Conference Record - Asilomar Conference on Signals, Systems and Computers | Year: 2015
Multiplication is the dominant operation for many applications implemented on field-programmable gate arrays (FPGAs). Although most current FPGA families have embedded hard multipliers, soft multipliers using lookup tables (LUTs) in the logic fabric remain important. This paper presents a novel circuit that combines radix-4 partial-product generation with addition (patent pending) and shows how it can be used to implement two's-complement multipliers. Single-cycle and pipelined designs for 8×8, 10×10, 12×12, 14×14 and 16×16 multipliers are compared to Xilinx LogiCORE IP multipliers. Proposed single-cycle parallel-tree multipliers use 35% to 45% fewer LUTs and have 9% to 22% less delay than LogiCORE IP multipliers. Proposed pipelined parallel-tree multipliers use 32% to 40% fewer LUTs than LogiCORE IP multipliers. Proposed parallel-array multipliers use even fewer LUTs than parallel-tree multipliers at the expense of increased delay. © 2014 IEEE.
Rutter M.A.,Behrend College
Journal of Great Lakes Research | Year: 2010
The Great Lakes Water Quality Agreement specifies "fish tumors or other deformities" as one of the 14 beneficial use impairments that can be used to declare a geographic area within the Great Lakes an Area of Concern (AOC). The International Joint Commission has suggested that the fish tumor impairment can be delisted when fish tumor incidence in the AOC does not exceed rates at unimpacted control sites. This paper presents a statistical technique utilizing Bayesian hierarchical logistic models to estimate tumor incidence on brown bullheads (Ameiurus nebulosus) in an AOC and in candidate least impacted control sites (LICS). Liver and skin tumor incidence are estimated using age, length, weight, and gender as possible covariates using a hierarchical framework to account for a sampling design in which sites are sampled over multiple years and/or at multiple sublocations within the site. By utilizing a Bayesian approach, estimates of uncertainty for tumor incidence in sites with no observed tumors can be obtained. The posterior distributions of tumor incidence can then be used to identify LICS for the watershed and subsequently compare the tumor incidence in the AOC to the LICS using a Bayesian form of the two one-side tests for equivalence procedure. Presque Isle Bay (Erie, PA) in the Lake Erie watershed is used as a case study to demonstrate the technique. © 2010 International Association for Great Lakes Research.
Williams J.L.,Behrend College
Plastics Engineering | Year: 2013
Project Management Maturity (PMM) is a new area within the study of Project Management. Each of the various Maturity Models level is demonstrated by various characteristics related to project planning, execution, management, and quality. A survey was constructed to estimate the project management maturity in the injection mold building industry. This survey was designed to produce a basic overview of the level of project management maturity and organizational size within the mold building industry. The results of the survey indicate that project management maturity does appear to change with organization size, but not within all the areas covered by this survey. Furthermore, these results also correlated with existing research in terms of project management processes utilized in SME's. Project planning, leading, and tracking showed the largest variation in maturity level. This variation is likely driven by the needs and resource availability of these organizations.
Williams D.M.,Behrend College
Astrobiology | Year: 2013
Terrestrial moons with masses >0.1 M⊕ possibly exist around extrasolar giant planets, and here we consider the energetics of how they might form. Binary-exchange capture can occur if a binary-terrestrial object (BTO) is tidally disrupted during a close encounter with a giant planet and one of the binary members is ejected while the other remains as a moon. Tidal disruption occurs readily in the deep gravity wells of giant planets; however, the large encounter velocities in the wells make binary exchange more difficult than for planets of lesser mass. In addition, successful capture favors massive binaries with large rotational velocities and small component mass ratios. Also, since the interaction tends to leave the captured moons on highly elliptical orbits, permanent capture is only possible around planets with sizable Hill spheres that are well separated from their host stars. © Mary Ann Liebert, Inc.
Mastroberardino A.,Behrend College
Applied Mathematics and Mechanics (English Edition) | Year: 2014
In this article, we present accurate analytical solutions for boundary layer flow and heat transfer of an incompressible and electrically conducting viscoelastic fluid over a linearly stretching surface subject to a transverse uniform magnetic field using the homotopy analysis method (HAM) for two general types of non-isothermal boundary conditions. In addition, we demonstrate that the previously reported analytical solutions for the temperature field given in terms of Kummer's function do not converge at the boundary. We provide a graphical and numerical demonstration of the convergence of the HAM solutions and tabulate the effects of various parameters on the skin friction coefficient and wall heat transfer. © 2014 Shanghai University and Springer-Verlag Berlin Heidelberg.
Walters E.G.,Behrend College
Conference Record - Asilomar Conference on Signals, Systems and Computers | Year: 2015
This paper presents a 24-bit significand multiplier for single-precision floating-point multiplication that is optimized for Xilinx FPGAs with 6-input LUTs. The design combines a 24 × 7 LUT-based multiplier and one embedded multiplier to implement a 24 × 24 unsigned multiplier. The proposed design uses 35% fewer LUTs and is 1.11 times faster than a LogiCORE multiplier that also uses one embedded multiplier. A truncated- matrix version that allows faithful rounding uses 78% fewer LUTs and is 1.17 times faster than a LogiCORE multiplier that uses one embedded multiplier. Both designs are comparable in speed to a LogiCORE multiplier that uses two embedded multipliers. © 2015 IEEE.