An accurate prefetching policy for object oriented systems

PhD ThesisIn the latest high-performance computers, there is a growing requirement for accurate prefetching(AP) methodologies for advanced object management schemes in virtual memory and migration systems. The major issue for achieving this goal is that of finding a simple way of accurately predicting the objects that will be referenced in the near future and to group them so as to allow them to be fetched same time. The basic notion of AP involves building a relationship for logically grouping related objects and prefetching them, rather than using their physical grouping and it relies on demand fetching such as is done in existing restructuring or grouping schemes. By this, AP tries to overcome some of the shortcomings posed by physical grouping methods. Prefetching also makes use of the properties of object oriented languages to build inter and intra object relationships as a means of logical grouping. This thesis describes how this relationship can be established at compile time and how it can be used for accurate object prefetching in virtual memory systems. In addition, AP performs control flow and data dependency analysis to reinforce the relationships and to find the dependencies of a program. The user program is decomposed into prefetching blocks which contain all the information needed for block prefetching such as long branches and function calls at major branch points. The proposed prefetching scheme is implemented by extending a C++ compiler and evaluated on a virtual memory simulator. The results show a significant reduction both in the number of page fault and memory pollution. In particular, AP can suppress many page faults that occur during transition phases which are unmanageable by other ways of fetching. AP can be applied to a local and distributed virtual memory system so as to reduce the fault rate by fetching groups of objects at the same time and consequently lessening operating system overheads.British Counci

The 1287 G/A polymorphism of the Norepinephrine Transporter gene (NET) is involved in Commission Errors in Korean children with Attention Deficit Hyperactivity Disorder

<p>Abstract</p> <p>Background</p> <p>Previous evidence supports the role of noradrenergic systems in ADHD, and norepinephrine transporter (NET) is critical in regulating the noradrenergic system. The present study aimed to investigate the association between NET gene polymorphism and the performance measures of the Continuous Performance Test (CPT) in Korean ADHD children.</p> <p>Methods</p> <p>Eighty-seven children (mean age = 9.23 ± 1.99 years) with ADHD were recruited from a university hospital. Genotypes of G1287A of the NET gene (SLC6A2) were analyzed. All participants completed the CPT, with performance measures of omission errors, commission errors, reaction time and reaction standardization computed. The relationship between G1287A polymorphisms and CPT performance measures was examined.</p> <p>Results</p> <p>There were 46 subjects with the G/G genotype, 35 subjects with the G/A genotype and 6 subjects with the A/A genotype. Among the three groups, there were no significant differences in the performance of CPTs. When dichotomized according to whether the subjects have the rare allele or not, subjects with the homozygous G/G genotype showed significantly lower commission errors compared to those without G/G genotypes (by independent T-test, t = -2.18, p = 0.026).</p> <p>Discussion</p> <p>Our study found a significant association between commission errors of the CPT and the G1287A genotype of the NET gene in Korean ADHD children. These findings suggest a protective role of the G/G genotype of the NET polymorphisms in the deficits of response inhibition in ADHD children.</p

Experimental Study on Coordinated Heading Control of Four Vessels Moored Side by Side

A floating type liquefied natural gas (LNG) bunkering terminal has been under development in Korea since 2014; the terminal is designed to receive LNG from an LNG carrier (LNGC) and transfer it to two other LNG bunkering shuttles (LNGBS) simultaneously. The operational feasibility of the LNG loading and unloading processes has been confirmed. When four vessels are moored side by side with mooring ropes and fenders, their positions must be maintained within the designed allowable criteria. In addition, the floating bunkering terminal (FLBT) has its own mooring system, an internal turret with catenary mooring lines and stern tunnel thrusters to maintain its own position and control the vessel heading. In this study, we investigated the operational feasibility of the FLBT during the LNG loading and unloading operations with four vessel mooring configurations and heading controls. A series of model tests was done in the ocean engineering basin of the Korea Research Institute of Ships and Ocean engineering. The motion responses of the four vessels were determined using an optical measurement system, and the tensile loads on ship-to-ship mooring ropes and the compressive loads on ship-to-ship fenders were measured using one-axis load cells. A white noise test was done and the results were compared with the numerical results for the purpose of validation. Then, four combined environmental conditions were presented both without heading control and with several heading control cases. Finally, we determined the available safe bunkering heading ranges taking into account the tensile loads on the mooring ropes

Signal Transduction Mechanisms Underlying Group I mGluR-mediated Increase in Frequency and Amplitude of Spontaneous EPSCs in the Spinal Trigeminal Subnucleus Oralis of the Rat

Group I mGluRs (mGluR1 and 5) pre- and/or postsynaptically regulate synaptic transmission at glutamatergic synapses. By recording spontaneous EPSCs (sEPSCs) in the spinal trigeminal subnucleus oralis (Vo), we here investigated the regulation of glutamatergic transmission through the activation of group I mGluRs. Bath-applied DHPG (10 μM/5 min), activating the group I mGluRs, increased sEPSCs both in frequency and amplitude; particularly, the increased amplitude was long-lasting. The DHPG-induced increases of sEPSC frequency and amplitude were not NMDA receptor-dependent. The DHPG-induced increase in the frequency of sEPSCs, the presynaptic effect being further confirmed by the DHPG effect on paired-pulse ratio of trigeminal tract-evoked EPSCs, an index of presynaptic modulation, was significantly but partially reduced by blockades of voltage-dependent sodium channel, mGluR1 or mGluR5. Interestingly, PKC inhibition markedly enhanced the DHPG-induced increase of sEPSC frequency, which was mainly accomplished through mGluR1, indicating an inhibitory role of PKC. In contrast, the DHPG-induced increase of sEPSC amplitude was not affected by mGluR1 or mGluR5 antagonists although the long-lasting property of the increase was disappeared; however, the increase was completely inhibited by blocking both mGluR1 and mGluR5. Further study of signal transduction mechanisms revealed that PLC and CaMKII mediated the increases of sEPSC in both frequency and amplitude by DHPG, while IP3 receptor, NO and ERK only that of amplitude during DHPG application. Altogether, these results indicate that the activation of group I mGluRs and their signal transduction pathways differentially regulate glutamate release and synaptic responses in Vo, thereby contributing to the processing of somatosensory signals from orofacial region

Applying Topographic Classification, Based on the Hydrological Process, to Design Habitat Linkages for Climate Change

The use of biodiversity surrogates has been discussed in the context of designing habitat linkages to support the migration of species affected by climate change. Topography has been proposed as a useful surrogate in the coarse-filter approach, as the hydrological process caused by topography such as erosion and accumulation is the basis of ecological processes. However, some studies that have designed topographic linkages as habitat linkages, so far have focused much on the shape of the topography (morphometric topographic classification) with little emphasis on the hydrological processes (generic topographic classification) to find such topographic linkages. We aimed to understand whether generic classification was valid for designing these linkages. First, we evaluated whether topographic classification is more appropriate for describing actual (coniferous and deciduous) and potential (mammals and amphibians) habitat distributions. Second, we analyzed the difference in the linkages between the morphometric and generic topographic classifications. The results showed that the generic classification represented the actual distribution of the trees, but neither the morphometric nor the generic classification could represent the potential animal distributions adequately. Our study demonstrated that the topographic classes, according to the generic classification, were arranged successively according to the flow of water, nutrients, and sediment; therefore, it would be advantageous to secure linkages with a width of 1 km or more. In addition, the edge effect would be smaller than with the morphometric classification. Accordingly, we suggest that topographic characteristics, based on the hydrological process, are required to design topographic linkages for climate change

Prognostic Significance of Proliferating Cell Nuclear Ant igen Exp ress ion in Soft Tissue Sarcomas of the Extremities

We analysed 40 patients with soft tissue sarcomas (STS) of the extremities to investigate the prognostic significance of the growth fraction of the tumor. The patients consisted of 27 males and 13 females, and the ages ranged from 18 to 70 years (median 46.9 years). Tumors were located in the thigh (47. 5%), forearm (15%), buttock (10%), shoulder (10%), axilla (5%), arm (5%), lower leg (5%), and foot (2.5%) in a descending order of frequency. Histologically, malignant fibrous histiocytoma (25%) and liposarcoma (25%) were the most common types, followed by synovial sarcoma (17.5%), malignant schwannoma (10%), and rhabdomyosarcoma (5%). Local recurrence ranging from 1 to 4 times (average 1.7 times) was noted in 18 cases (45%). Distant metastasis was found in 5 out of 30 patients (16.7%), and the lung, liver, and abdominal wall were the predilection sites. Cumulative survival rates of all STS studied were 76% and 58% in 2 years and 5 years, respectively. Univariate analysis revealed that patient's age, surgical stage, histologic grade, differentiation of tumor cells, mitotic count, and proliferative index were related to survival. Among known parameters of histologic grading, only mitotic count was correlated with proliferative index. Multivariate analysis showed that patient's age, surgical stage and proliferative index were significant prognostic factors. This study indicates that the proliferative index using the antibody against proliferating cell nuclear antigen is useful to assess the prognosis of STS

Effects of Blood Flow Restriction Non-Linear Periodization Strength Training on Muscle Strength and Function in Elite Athletes

PURPOSE To evaluate the effects of resistance exercise with intermittent blood flow restriction (BFR) on the muscle thickness, maximal strength, and isokinetic muscular function (strength, power, endurance) in high school field hockey athletes. METHODS The BFR group (n=10, 16.1±1.1 years, 172.8±3.9 cm, 66.2±3.9 kg) and the control (CON) group (n=10, 16.60±1.17 years, 172.5±2.3 cm, 65.7±2.9 kg) participated in the same nonlinear periodic training program, however different weight loading (%RM) was applied depending on whether or not BFR was applied. In this study, the systolic blood pressure was set as the blood flow compression strength, and a BFR prop belt was used. After the 8-week training period was over, the degree of improvement in body composition, 1 repetition maximum (1RM), and isokinetic muscle function among groups was compared to determine the effect of training by blood flow restriction. RESULTS The cross-sectional area of the thighs of athletes who applied BFR was significantly increased than that of the CON (p.05). In the results of improving the muscle strength (1RM and 60º/sec) of the athletes who applied the BFR, there was no significant difference between the groups in muscle power and muscular endurance. CONCLUSIONS Non-linear strength training with BFR might be considered to be an effective method for improving muscle hypertrophy and maximum strength of athletes. The muscle endurance and muscle power method once a week, which was not effective in improving the muscle power and muscular endurance of high school male hockey players