Survey on blood supply chain management: Models and methods

A low-power comparator is presented. pMOS transistors are used at the input of the preamplifier of the comparator as well as the latch stage. Both stages are controlled by a special local clock generator. At the evaluation phase, the latch is activated with a delay to achieve enough preamplification gain and avoid excess power consumption. Meanwhile, small cross-coupled transistors increase the preamplifier gain and decrease the input common mode of the latch to strongly turn on the pMOS transistors (at the latch input) and reduce the delay. Unlike the conventional comparator, the proposed structure let us set the optimum delay for preamplification and avoid excess power consumption. The speed and the power benefits of the comparator were verified using solid analytical derivations, process–VDD–temperature corners, and Monte Carlo simulations along with silicon measurements in $0.18~\mu \text{m}$ . The tests confirm that the proposed circuit reduces the power consumption by 50% and provides 30% better comparison speed at the same offset and almost the same noise budgets. Moreover, the comparator provides a rail-to-rail input $V_{\text {cm}}$ range in $f_{\text {clk}} = 500$ MHz.

A Low-Power High-Speed Comparator for Precise Applications

Environmental effect for a complex green supply-chain management to control waste: A sustainable approach

Inventory management in blood supply chain considering fuzzy supply/demand uncertainties and lateral transshipment

Blood shortage may lead to immeasurable losses. But the perishable nature of blood products limits the possibility of storing a large amount of it, and the quality of blood products reduces rapidly with transportation time. Specifically, in China, the management of blood products is even more complicated due to the significant demand for clinical blood, which increases every single year because of the reformation of the health system and the resulting scale expansion of hospitals. In this research, we aim to optimize the blood product scheduling scheme by constructing a vendor-managed inventory routing problem (VMIRP) for blood products, which balances the supply and demand such that the relevant operational cost is minimized. Then a decomposition-based algorithm is developed to solve the proposed mathematical model efficiently. Based on a series of numerical experiments of platelets, we obtain and examine the distribution plan and optimal transportation path over the planning horizon. In addition to the illustrated high algorithm efficiency, the computation results show that the VMIRP scheme can considerably decrease the operational cost of the blood supply chain.

Scheduling the distribution of blood products: A vendor-managed inventory routing approach

Despite significant advancements in medicine, human blood is still a scarce resource. Only humans produce it, and there is currently no other product or alternative chemical process that can be used to generate blood. For this reason, blood is a vital commodity in healthcare systems. Since blood is also a perishable product, its inventory management is difficult. The challenge is in holding enough stock to ensure a high level of supply while keeping losses from expiration at a minimum. This research will investigate blood inventory management in a hospital, and develop a mathematical model to manage blood ordering and issuing. This study will account for the fact that blood demand and supply are uncertain, and blood transshipment is possible. The proposed model considers the substitution relations among various blood types in the blood transfusion process to minimize blood shortage and wastage. Since the proposed model contains uncertain parameters, the use of chance constraint programming creates a deterministic counterpart. The deterministic model is then adapted to include approximations to remove non-linearity. Finally, a numerical experiment is designed to exhibit the model’s results and analyze the influence of different parameters on blood inventory management.

Blood inventory management in hospitals: Considering supply and demand uncertainty and blood transshipment possibility

A low-power high-speed two-stage dynamic comparator is presented. In this circuit, PMOS transistors are used at the input of the first and second stages of the comparator. At the evaluation phase, the second stage is activated after the first stage with a predetermined delay to achieve a controllable pre-amplifier gain. Also, the first stage is turned off after the delay to reduce overall power consumption. Simulation results in 0.18 μτη CMOS technology, prove that the proposed circuit reduces the power consumption by a factor of two and reduces comparison time as large as 210ps in the same budget of offset voltage compared to the conventional circuit. Moreover, the offset voltage and power consumption of the comparator trades with the speed which is simply controlled by the delay of the second stage. As a result, a low-power comparator for given offset and speed requirements can be designed efficiently.

A low-power high-speed comparator for analog to digital converters

Investigation of TLP behavior under tendon damage

Stability of Tension Leg Platforms (TLP) is sensitive to tendons situations. Therefore, behavior and exact calculation of stiffness matrix of TLP is important for dynamic analysis and investigation of TLP in intact and damaged tendon conditions is necessary to accurate and reliable design of TLP. In this paper deals with dynamic analysis of TLP when tendons are intact and one or three tendons are damaged. Static stability of TLP in damage condition has been studied and static offsets have been estimated, then stiffness of surge, heave and pitch has been derived. Finally, responses of heave and pitch for three load conditions have been predicted.

https://ijcoe.org/files/site1/user_files_c8faec/admin-A-10-1-2-3ea59dc.pdf

Dynamic Analysis of TLP in Intact and Damaged Tendon Conditions

Fast, accurate and efficient sensing is of important aspects in cognitive radio technology. We propose a simple, practical design for two-dimensional sensing in spectral and spatial domain. In fact detection and localization of signal are done in a wide band elliptical array. Two sets of phase differences help to fast calculation of frequency and angle of arrival. We study the constraints, advantages and accuracy of the method.

Ali Ahmadi

Papers

Blood inventory management in hospitals: Considering supply and demand uncertainty and blood transshipment possibility

A low-power high-speed comparator for analog to digital converters

Investigation of TLP behavior under tendon damage

Dynamic Analysis of TLP in Intact and Damaged Tendon Conditions

Two dimensional sensing for cognitive radio applications using antenna array