Operations Research, Systems Engineering and Industrial Engineering Commons^™

Revised Reference Curves For Bone Mineral Content And Areal Bone Mineral Density According To Age And Sex For Black And Non-Black Children: Results Of The Bone Mineral Density In Childhood Study, Babette S. Zemel, Heidi J. Kalkwarf, Vicente Gilsanz, Joan M. Lappe, Sharon Oberfield, John A. Shepherd, Margaret M. Frederick, Xangke Huang, Ming Lu, Soroosh Mahboubi, Thomas N. Hangartner, Karen K. Winer

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Context: Deficits in bone acquisition during growth may increase fracture risk. Assessment of bone health during childhood requires appropriate reference values relative to age, sex, and population ancestry to identify bone deficits.

Objective: The objective of this study was to provide revised and extended reference curves for bone mineral content (BMC) and areal bone mineral density (aBMD) in children.

Design: The Bone Mineral Density in Childhood Study was a multicenter longitudinal study with annual assessments for up to 7 yr.

Setting: The study was conducted at five clinical centers in the United States.

Participants: Two thousand fourteen healthy children (992 …

Reducing Selection Bias In Case-Control Studies From Rare Disease Registries, J. Alexander Cole, John S. Taylor, Thomas N. Hangartner, Neal J. Weinreb, Pramod K. Mistry, Aneal Khan

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Background: In clinical research of rare diseases, where small patient numbers and disease heterogeneity limit study design options, registries are a valuable resource for demographic and outcome information. However, in contrast to prospective, randomized clinical trials, the observational design of registries is prone to introduce selection bias and negatively impact the validity of data analyses. The objective of the study was to demonstrate the utility of case-control matching and the risk-set method in order to control bias in data from a rare disease registry. Data from the International Collaborative Gaucher Group (ICGG) Gaucher Registry were used as an example.

Methods: …

Recording Of Elevated Temperature Fatigue Crack Growth Data By Dcpd System, N. Ramachandran, N. Arakere, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The growth of "long" fatigue cracks, in α-β titanium alloy forging, subjected to cyclic stresses, is studied in this paper. The fatigue crack growth rate (FCGR) data were recorded at room temperature, 350, 450, 550 and 650°F using the Direct Current Potential Difference (DCPD) technique. The DCPD method, used in this investigation, was found to record and correlate the potential difference in terms of crack growth rate (da/dN) and Mode I stress intensity factor range satisfactorily. Various factors related to error minimization and calibration equations for compact tension specimens have been elaborated. Also discussed were the means to enhance the …

An Exploratory Study Of Mixed-Width Aisle Layouts For Order Picking In Distribution Centers, Corinne H. Mowrey

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Order picking is arguably the most expensive operational activity for a distribution center (DC), constituting upwards of 50% of total operating costs. Designing an optimum order picking system (OPS) for a DC depends on several system parameters, such as aisle layout, storage system configuration, storage policy, picking method, and picking strategy. From an aisle layout standpoint, traditional DCs utilize either entirely wide or entirely narrow aisles in their picking systems. Wide aisles allow pickers to pass each other, reducing blocking and requiring fewer pickers. However, the space required for wide-aisle systems is high. Narrow aisles utilize less space than wide …

Cognitive Cyber Weapon Selection Tool Empirical Evaluation, Preethi Vinayak Ponangi

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Keeping in pace with the latest technological innovations in the cyber world, the misuse of this powerful infrastructure has also increased proportionally. Although a lot of recent attacks have been documented in the mainstream media, counter measures for cyber defense mechanism have only received some attention in the recent research literature. Most of the global attacks in the cyber space have proved to be carefully planned premeditated attacks. Considering that most of these attacks are co-coordinated by humans, a new area of psychological weaponry is being investigated by the research community. This study aims to empirically evaluate the effectiveness of …

Drop-Shipping At A Promotional Products Distributor, Ramanan Veeraragavan

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During the current economic times, companies are trying to reduce costs by incorporating new strategies into their business plan. Supply chain, in particular the distribution network is one area where an improvement can bring in a healthy return on investment to a company. Drop-shipping is a distribution strategy whereby customer orders are fulfilled by directly delivering products from manufacturer's facility, instead of storing these products at the warehouse. Drop-shipping helps in reducing inventory and material handling costs at the warehouse, but may increase transportation costs due to frequent shipments. This research was motivated by the current operations at a promotional …

Scheduling Surgical Cases In A Constrained Environment, Bharathwaj Vijayakumar

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This research examines a complex surgical case scheduling problem for a publicly-funded hospital in the Midwest United States. Publicly-funded hospitals are typically under tight budget constraints and these hospitals strive to maximize the utilization of their resources such as beds, staff, equipment, operating rooms, etc. These resources are relatively fixed for a publically funded hospital. A manual scheduling approach followed by this hospital does not guarantee optimal solutions and consequently has led to large variation in the utilization of resources. This real-world problem is described in this research as a multi-day, multi-resource, and patient-priority-based surgical case scheduling problem with the …

Determining The Optimal Aisle-Width For Order Picking In Distribution Centers, Sheena R. Wallace-Finney

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Many companies use distribution centers (DC) as hubs for storing and distributing products to customers (e.g., wholesalers, retailers, or consumers). Order picking, a critical activity in every DC, refers to retrieving products from the storage locations to fulfill customer orders. It accounts for over 50% of the DC operating cost. Order picking system design involves several decisions, such as layout of the picking area, storage policy, picking method, material handling equipment, and information technology, to name a few. Aisle configuration (number, length, width, and orientation) is a critical layout decision as it directly affects picker productivity and required space. Previous …