Routing Protocols in Delay Tolerant Networks: Comparative and Empirical Analysis

Wireless Personal Communications - A Delay Tolerant Network (DTN) is a network capable of handling long delays and data loss efficiently in various challenged scenarios and environments. Owing to...     

The Effect of Distribution on Product Temperature Profile in Thermally Insulated Containers for Express Shipments

An uninterrupted cold chain is a continual series of storage and distribution activities that maintain a specific temperature or temperature range. Cold chain solutions typically involve excessive packaging to ensure that the desired product temperature is maintained through the distribution process, thereby increasing the logistics‐related costs. There is a myriad of solutions available for shipping temperature‐sensitive products, including those constructed with a variety of packaging materials as well as refrigerants. Although static characteristics for thermally insulated packaging solutions such as the R‐values of package systems as well as the melting points and heat absorption rates of various refrigerants have been studied in the past, none of the past studies have evaluated the effect of comprehensive distribution on the reliability of the cold chain packaging solutions. This research was undertaken to study the temperature profiles for factors such as different densities for a given thickness of thermally insulating material, wall thicknesses and distribution environments for four different types of materials—polyurethane, virgin expanded polystyrene, recycled content expanded polystyrene and vacuum‐insulated panels. The temperature range of 2 °C–8 °C, critical for pharmaceutical drugs and vaccines, was targeted. An interesting regression‐based finding was that the interaction between the R‐value and the wall thickness significantly influenced the length of time the thermally insulated packages stayed in the desired range of 2 °C–8 °C . The findings of this study will be decisive in designing cost‐efficient and practical single‐use cold chain transportation solutions for temperature‐sensitive products. Copyright © 2012 John Wiley & Sons, Ltd.     

A Fully Autonomous Microrobotic Endoscopy System

In this paper, design of an autonomous microrobotic endoscopy system is presented. The proposed microrobotic endoscope is a vision-guided device, developed to facilitate navigation inside a human colon. The design of the entire system is divided into three areas viz. design of a microrobotic carrier, path planning and guidance, and an off-board control system. A microrobotic design based on pneumatic mechanisms to achieve locomotion and steering is explained. General mathematical analysis governing the differential steering of the robotic tip is also described. The path planning of the microrobot is carried out based on the sensory fusion utilising the quantitative parameters from the captured images and the tactile sensors. A real-time image segmentation scheme is described for extracting the lumen from endoscopic images. An off-board control system to control the directional movements of the microrobot is also explained. The proposed endoscopy system was tested with physical models and animal colons and the experimental observations are presented.     

Communication interface in a physical simulator for robotic palletization

This paper addresses the issues relating to the communication channels in a physical simulator for flexible automation of a palletization task. The simulator used in our work involves an IBM-7545 robot, a personal computer and an Allen-Bradley Programmable Logic Controller (PLC). The communications relating to the Robot/PC interface and the PLC/PC interface are discussed.

The palletization station design requires that decisions on pallet pattern are made dynamically by a program running on the personal computer. The Robot/PC communication interface is necessary to transmit these decisions to the robot controller for execution. This communication is to be achieved using BASIC language and AML 4.1 as the software platforms.

The PLC has the task of controlling the transport of the boxes coming to the palletization station. The program for deciding the pallet pattern, running on the personal computer, needs real-time information on the counts of boxes of different sizes that are arriving for palletization. The PLC/PC interface serves to provide this information.     

Design and development of a physical simulator for robotic palletization

This paper discusses the design and development of a physical simulator for robotic palletization. The design is aimed at two objectives. One, to provide a test bed for studying issues relating to automation of palletization and second, to provide a teaching tool for some common elements of material handling automation. The major hardware components of the system are an IBM 7545 robot, a Personal Computer, an Allen-Bradley Programmable Logic Controller (PLC), Conveyors and a Bar Code Reader. The software components include the IBM AML 4.1 language, PLC Software and BASIC software for the BASIC Module of the PLC.     

An Approach for Establishing Enterprise Data Standards

Avoid the common pitfalls experienced by many organizations that have established enterprise data standards by following a straightforward process. Standards should be defined around a simple framework and be borrowed from third parties or vendors wherever possible to save time. It is better to reuse, rather than reinvent or create standards. To be used successfully, standards must be easy to understand, have a proven track record, be easy to use, and be readily available. Standards should be maintained in a central repository such as Lotus Notes or on an intranet Web site so that they are readily accessible to project teams.     

Wireless data: Systems,standards, services

Wireless data products and services being proposed today include exotic mixes of services and technologies: packet transport over cellular circuits, facsimile service over Cellular Digital Packet Data (CDPD), voice and video over wireless LANs, and everything in between. Data networking terms that seem to have a clear meaning-data-link, network and transport layers; circuit-mode and datagram; connection-less and connection-oriented-in fact have meaning only in context. Thus TCP, a reliable packet transport protocol, is being used in CDMA circuit-mode data to provide a reliable data-link layer for the error-prone wireless link. IP datagrams will be transported over cellular links using dedicated channels with call establishment, possibly per packet. Market demands for timely solutions, competition between alternative technologies and the plethora of alternative fora for standards development are driving wireless data into fragmented directions. The primary constraints come from the limited spectrum, the need for security in the presence of mobility and the size and weight of mobile terminals and devices. Often the optimization for the latter constraints is sacrificed at the altar of the former drivers. Based upon our experience and work with standards and systems we attempt to put wircless data into perspective. We compare and contrast major services and products and identify the choices that were made and why.We acknowledge the contributions of our colleagues at AT&T Bell Laboratories: Ken Budka, Mooi Choo Chuah, Bharat Doshi, Subra Dravida, Richard Ejzak and On-Ching Yue.     

Near infrared light-induced disassembly of polymeric micelles based on methylene blue conjugated polyethylene glycol

Light-sensitive drug delivery systems are considered ideal for applications in the biomedical fields for their ability to release the payload in an on-demand spatiotemporal controlled manner through the manipulation of the light source. Among the broad radiation spectrum, near infrared (NIR) light is considered advantageous compared to UV and visible light, due to its inherently lower photodamage to normal tissues and deeper penetration to lesion areas. In this study, we report a successful synthesis of a polymer capable of undergoing partial degradation upon irradiation with NIR light by conjugating 10-N-carbamoyl linkage methylene blue (MB) moiety, a NIR photocleavable ligand, with polyethylene glycol (PEG). Through effective coupling of MB, a hydrophobic moiety, to the hydrophilic PEG molecule, an amphiphilic polymer was synthesized, as demonstrated by a lowered surface tension (55 mN/m at 0.1% wt/vol). Subsequently, photo-induced reversal of surface activity associated with self-assembled structure disruption, was displayed by surface tension measurements, size distribution analysis, and burst release profile of paclitaxel (PTX) from polymeric micelles upon the exposure to NIR irradiation.