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91.
In this paper, an improved DRP method to schedule multi-echelon distribution network is proposed such that order-quantities and order points are dynamically obtained to meet the demand in just in time concept and minimize the out-of-stock probability. The order scheduling method reflects the dynamic characteristics of inventory level changes in the regional distribution centers and the central distribution center. The experiment has been done with various demand distributions, forecast error distributions and lead times. The proposed method was compared with the traditional DRP-based scheduling methods which use different lot-sizing and order point decision techniques. From the result, it is found that the proposed heuristic method yields preferable lot-sizing schedules. 相似文献
92.
Lee Y.-I. Park K.-H. Lee J. Lee C.-S. Yoo H.J. Kim C.-J. Yoon Y.-S. 《Journal of microelectromechanical systems》1997,6(3):226-233
A new method for dry etching of silicon dioxide for surface micromachining is presented to obtain very compliant polysilicon microstructures with negligible stiction problem and to greatly simplify the overall releasing procedure as well. By etching the sacrificial silicon dioxide with hydrofluoric acid (HF) vapor instead of conventional aqueous HF solution, the need for subsequent rinsing and an elaborate drying procedure is eliminated. Condensation of water on the etch surface is first identified as the cause that prevented the success of HF vapor release in the past. Use of an anhydrous HF/CH3OH mixture under low pressure solves the problem of water condensation and enables us to take advantage of vapor-phase etching (VPE) for surface micromachining. The mechanism of oxide etching with the HF/CH3OH mixture is explained, and the developed VPE system is described and characterized. Polysilicon cantilevers up to 1200 μm in length are successfully released with this HF VPE technique. The beams tested are 2 μm thick with a 2-μm gap from the substrate, and no antistiction dimples are used. The fabricated structures are observed using both scanning electron microscopy (SEM) and an optical profilometer. The reported VPE technique provides a robust releasing method for polysilicon microstructures and is compatible with integrated circuit (IC) fabrication, even including cluster processors 相似文献
93.
Given a set P of polygons in three-dimensional space, two points p and q are said to be visible from each other with respect to P if the line segment joining them does not intersect any polygon in P . A point p is said to be completely visible from an area source S if p is visible from every point in S . The completely visible region
CV(S, P) from S with respect to P is defined as the set of all points in three-dimensional space that are completely visible from S .
We present two algorithms for computing CV(S, P) for P with a total of n vertices and a convex polygonal source S with m vertices. Our first result is a divide-and-conquer algorithm which runs in O(m
2
n
2
α(mn)) time and space, where α(mn) is the inverse of Ackermann's function. We next give an incremental algorithm for computing CV(S,P) in O(m
2
n+mn
2
α(n)) time and O(mn+n
2
) space. We also prove that CV(S,P) consists of Θ(mn+n
2
) surface elements such as vertices, edges, and faces.
Received November 16, 1995; revised November 11, 1996. 相似文献
94.
Most of the results on decentralized supervisory control are based on supervisors that make unconditional decisions: "enable" and "disable." In this paper, we introduce and study the properties of decentralized supervisory control architectures where supervisors are allowed to make conditional decisions in addition to unconditional decisions. The conditional decisions we consider are of the form: "enable if nobody disables" and "disable if nobody enables." We characterize the notion of conditional coobservability that appears in the necessary and sufficient conditions for the existence of supervisors in the context of such control architectures. This condition relaxes the previous notions of coobservability for unconditional architectures. The key properties of conditional coobservability are studied. We develop a polynomial-time algorithm for verifying the notion of conditional coobservability. A polynomial-time method of partitioning the controllable events between "enable by default" and "disable by default" is presented. 相似文献
95.
96.
Young-Soo Seo Weui-Bong Jeong Wan-Suk Yoo Ho-Kyeong Jeong 《Journal of Mechanical Science and Technology》2005,19(2):625-633
A finite element vibration analysis of thin-watled cylindrical shells conveying fluid with uniform velocity is presented The
dynamic behavior of thin-walled shell is based on the Sanders’ theory and the fluid in cyhndrical shell is considered as inviscid
and incompressible so that it satisfies the Laplace’s equation A beam-like shell element is used to reduce the number of degrees-of-freedom
by restricting to the circumferential modes of cylindrical shell An estimation of frequency response function of the pipe
considering of the coupled effects of the internal fluid is presented A dynamic coupling condition of the interface between
the fluid and the structure is used The effective thickness of fluid according to circumferential modes is also discussed
The influence of fluid velocity on the frequency response function is illustrated and discussed The results by this method
are compared with published lesults and those by commercial tools 相似文献
97.
98.
Organic-based magnets are intriguing materials with unique magnetic and electronic properties that can be tailored by chemical methodology. By using molecular layer deposition (MLD), we demonstrate the thin film fabrication of V[TCNE: tetracyanoethylene](x), of the first known room temperature organic-based magnet. The resulting films exhibit improvement in surface morphology, larger coercivity (80 Oe), and higher Curie temperature/thermal stability (up to 400 K). Recently, the MLD method has been widely studied to implement fine control of organic film growth for various applications. This work broadens its application to magnetic and charge transfer materials and opens new opportunities for metal-organic hybrid material development and their applications in various multilayer film device structures. Finally, we demonstrate the applicability of the multilayer V[TCNE](x) as a spin injector combining LSMO, an standard inorganic magnetic semiconductor, for spintronics applications. 相似文献
99.
100.
The abuse or misuse of antibiotics has caused the emergence of extensively drug-resistant (XDR) bacteria, rendering most antibiotics ineffective and increasing the mortality rate of patients with bacteremia or sepsis. Antimicrobial peptides (AMPs) are proposed to overcome this problem; however, many AMPs have attenuated antimicrobial activities with hemolytic toxicity in blood. Recently, AMPR-11 and its optimized derivative, AMPR-22, were reported to be potential candidates for the treatment of sepsis with a broad spectrum of antimicrobial activity and low hemolytic toxicity. Here, we performed molecular dynamics (MD) simulations to clarify the mechanism of lower hemolytic toxicity and higher efficacy of AMPR-22 at an atomic level. We found four polar residues in AMPR-11 bound to a model mimicking the bacterial inner/outer membranes preferentially over eukaryotic plasma membrane. AMPR-22 whose polar residues were replaced by lysine showed a 2-fold enhanced binding affinity to the bacterial membrane by interacting with bacterial specific lipids (lipid A or cardiolipin) via hydrogen bonds. The MD simulations were confirmed experimentally in models that partially mimic bacteremia conditions in vitro and ex vivo. The present study demonstrates why AMPR-22 showed low hemolytic toxicity and this approach using an MD simulation would be helpful in the development of AMPs. 相似文献