A quantitative measure for degree of automation and its relation to system performance and mental load

In this paper we quantitatively model degree of automation (DofA) in supervisory control as a function of the number and nature of tasks to be performed by the operator and automation. This model uses a task weighting scheme in which weighting factors are obtained from task demand load, task mental load, and task effect on system performance. The computation of DofA is demonstrated using an experimental system. Based on controlled experiments using operators, analyses of the task effect on system performance, the prediction and assessment of task demand load, and the prediction of mental load were performed. Each experiment had a different DofA. The effect of a change in DofA on system performance and mental load was investigated. It was found that system performance became less sensitive to changes in DofA at higher levels of DofA. The experimental data showed that when the operator controlled a partly automated system, perceived mental load could be predicted from the task mental load for each task component, as calculated by analyzing a situation in which all tasks were manually controlled. Actual or potential applications of this research include a methodology to balance and optimize the automation of complex industrial systems.     

Determination of InN/Diamond Heterojunction Band Offset by X-ray Photoelectron Spectroscopy

Diamond is not only a free standing highly transparent window but also a promising carrier confinement layer for InN based devices, yet little is known of the band offsets in InN/diamond system. X-ray photoelectron spectroscopy was used to measure the energy discontinuity in the valence band offset (VBO) of InN/diamond heterostructure. The value of VBO was determined to be 0.39 ± 0.08 eV and a type-I heterojunction with a conduction band offset (CBO) of 4.42 ± 0.08 eV was obtained. The accurate determination of VBO and CBO is important for the application of III-N alloys based electronic devices.     

Determination of threshold exposure and intensity for recording holograms in thick green-sensitive acrylamide-based photopolymer

For optical data storage applications, it is essential to determine the lowest intensity (also known as threshold intensity) below or at which no data page or grating can be recorded in the photosensitive material, as this in turn determines the data capacity of the material. Here, experiments were carried out to determine the threshold intensity below which the formation of a simple hologram--a holographic diffraction grating in a green-sensitized acrylamide-based photopolymer--is not possible. Two main parameters of the recording layers--dye concentration and thickness--were varied to study the influence of the density of the generated free radicals on the holographic properties of these layers. It was observed that a minimum concentration per unit volume of free radicals is required for efficient cross-linking of the created polymer chains and for recording a hologram. The threshold intensity below which no hologram can be recorded in the Erythrosin B sensitized layers with absorbance less than 0.16 was 50 μW/cm(2). The real-time diffraction efficiency was analyzed in the early stage of recording. It was determined that the minimum intensity required to obtain diffraction efficiency of 1% was 90 μW/cm(2), and the minimum required exposure was 8 mJ/cm(2). It was also determined that there is an optimum dye concentration of 1.5 × 10(-7) mol/L for effective recording above which no increase in the sensitivity of the layers is observed.     

Culture medium for protocorm differentiation in Dendrodium candidum Wall. ex Lindl

Effects of basal culture medium, sucrose concentration, natural extracts and phytohormones on protocorm differentiation were studied. The suitable medium for protocorm differentiation has been found to be 1/2Ms basal medium plus 2% w/v sucrose, 2mg/L BA, 0.2mg/L NAA and 20% (w/v) potato extract.     

EEG-study of perception of two-dimensional images of three-dimensional objects

We developed a corneal thickness mapping system with ultrasound biomicroscopy (UBM). Perpendicular section ultrasonic echo images of cornea within a radius of 2.5 mm from the center of the cornea in normal eyes were digitized and analyzed with a computer. Pachymetric maps were then represented by a color scale. Individual corneal thickness mapping will be necessary in refractive surgery and helpful in understanding pathologic states.     

Evaluation of the efficacy of thiamine and pyridoxine in the treatment of symptomatic diabetic peripheral neuropathy

Our purpose in this study was to determine the effects of cheilectomy on the mechanics of dorsiflexion of the first metatarsophalangeal (MTP) joint. Ten fresh-frozen cadaver feet were utilized, of which two demonstrated radiographic evidence of hallux rigidus. Each specimen was rigidly mounted on a custom-made slide tray that was articulated with a hinge mechanism designed to dorsiflex the first MTP joint. Range-of-motion measurements were made on the first MTP joint. Cheilectomy of 30% of the metatarsal head diameter was performed. Lateral radiographs with the beam centered on the MTP joint were taken with the joint at neutral, 20 degrees, 40 degrees, and at the limits of dorsiflexion. This process was repeated after a 50% cheilectomy was performed. The radiographs were examined for changes in joint congruence and in patterns of surface motion as the hallux moved from neutral to full dorsiflexion. Instant centers of rotation were determined by a method first described by Rouleaux. We constructed surface velocity vectors to describe patterns of motion of the first MTP joint. The mean dorsiflexion of the first MTP joint was 67.9 degrees and increased to 78.3 degrees after 30% cheilectomy. The increase in dorsiflexion was significantly greater in the two specimens with hallux rigidus (33%) than in the other specimens (12.1%). After both levels of cheilectomy, the proximal phalanx demonstrated pivoting at the resection site on the metatarsal head. This pivoting resulted in abnormal motion patterns across the MTP joint. Normal sliding motion predominated in early dorsiflexion, with compression peaking at the end stage of dorsiflexion, producing jamming of the articular surfaces. Cheilectomy significantly increased dorsiflexion of the MTP joint, but resulted in abnormal motion patterns. The increase in dorsiflexion resulted from pivoting of the proximal phalanx on the metatarsal head, resulting in anomalous velocity vectors and compression across the MTP joint.