Matching Unit Research Articles

High-Power Test of Chemical Vapor Deposited Diamond Window for an ECRH System in SST-1

High-power tests on chemical vapor deposited (CVD) diamond window are carried out using 82.6-GHz Gyrotron. To test CVD diamond window with calorimetric dummy load, a matching optic unit is designed and fabricated with special profiled mirrors. The mirrors are fabricated by Gycom Russia and a mirror box assembly is fabricated at Institute for Plasma Research. The mirrors and mirror box are cooled with water. The mirror box consists of four arc detectors for the protection of window. The CVD diamond window is connected to a dummy load with this mirror box. The alignment of mirror is done during the testing of CVD window in pulsed condition. After achieving the desired Gaussian pattern at the exit of mirror box, system is connected to a dummy load for continuous wave test. The CVD window is tested maximum power up to 60 kW in pulse duration of 600 s.

Impact of engaging middle management in practice interventions on staff support and learning culture: a quasi-experimental design

This study evaluated the impact of different levels of engaging middle management in ward based strategies implemented by a project educator. The challenge for learning in practice is to develop effective teams where experienced staff engage and foster learning with students and other novice staff. A quasi-experimental pre- and post- intervention four group design was conducted from November 2009 to May 2010 across four general surgical and four general medical inpatient matched units in two settings in South East Queensland, Australia. Staff survey data was used to compare control and intervention groups (one actively engaging nurse managers) before and after 'practice learning' interventions. The survey comprised demographic data and data from two validated scales (support instrument for nurses facilitating learning and clinical learning organisational culture). Number of surveys returned pre- and post-intervention was 336 from 713 (47%). There were significant differences across many subscales pertaining to staff perception of support in the intervention groups, with only one change in the control group. The number of significant different subscales in the learning culture was also greater when middle management supported the intervention. Middle management should work closely with facilitators to assist embedding practice interventions.

Determining the reliable minimum unit capacitance for the DAC capacitor array of SAR ADCs

The layout area of an SAR ADC is mainly occupied by its DAC capacitor array. Since there are 2N matched unit capacitors employed for a binary-weighted N-bit DAC, selecting a small unit capacitance is the key to reducing the layout area of the capacitor array, and accordingly reduce the total area of an SAR ADC for size-constrained implantable or wearable applications. In this paper the matching error and thermal noise of the capacitor array are considered systematically for the whole SAR ADC to determine the minimum unit capacitance. The statistical analysis shows that the matching error of the capacitor array depends not only on the matching parameter of the given process but also on the confidence level of the design, while thermal noise analysis shows that thermal noise of the capacitor array does not equal that of either the unit capacitor or the total capacitance of the capacitor array. The calculations for the matching error and thermal noise of a 10-bit DAC show that although the matching error is 7 times bigger, thermal noise which consumes 1/8 error budget should not be ignored for determining the reliable minimum unit capacitance. An iterative algorithm is proposed to find the minimum value when both matching error and thermal noise are considered. A 10-bit SAR ADC adopting an 89.44fF poly–poly unit capacitor in the 0.35μm CMOS process validated the method.

Matching of the ECRH transmission line of W7-X

The polarization of the directed ECRH power has to be matched to the plasma boundary with respect to the magnetic field at the density gradient region close to the last closed flux surface (LCFS). This is achieved by means of grooved mirrors, which provide the required polarization and which are part of the matching optics unit (MOU) of the gyrotrons. The RF radiation from the gyrotrons has to pass typically 16 mirrors in a complex three-dimensional arrangement in order to reach the plasma. The paper discusses the modeling of the ECRH transmission in order to find the required polarizer adjustment for each possible injection angle and plasma wave type (O- or X-mode). This includes the calculation of the polarization state on the plasma boundary, the back-propagation through the transmission line up to the MOU and finally the calculation of the corresponding angles of both polarizers.

Spiking Self-organizing Maps for Classification Problem

Abstract In Self-Organizing Maps (SOM) learning, preserving the map topology to simulate the real input features is one of the most important processes. This is done by training the weight values within the Best Matching Unit (BMU) neighborhood. Improper input feeding will cause failure in identifying the potential BMU which will lead to poor map topology. Many studies have been done to optimize the structure of SOM's topology using Artificial Neural Networks (ANN).Spiking Neural Network (SNN) is the third generation of ANN, where information are transferred from one neuron to other using spikes, and processed to trigger response as an output. Current researches have proven that SNN would be an alternative solution for enhancing ANN learning due to its superiority in capturing the internal relationship of neurons. This paper proposes embedded spiking neurons for Kohonen's Self-organizing Maps (SOM) learning to improve its learning process. The proposed Spiking SOM is divided into four main phases. Phase 1 involves the development of the training sample for SOM learning through neural coding schemes. In Phase 2, the spike values are fed into the training process and potential weights are generated. Phase 3 identifies and labels the outputs from the Spiking SOM classification based on the features and characteristics. Finally, in Phase 4, proposed Spiking SOM model is validated using classification accuracy, error quantization and statistical tests using Pearson correlation. Early experiment is conducted using the 1D coding schemes for transforming dataset into spike times with hexagonal lattice structure of SOM network. Result on cancer dataset shows that the tested model has produced feasible classification accuracy with low quantization error. It shows that the 1D coding is capable in preserving the features in the input neurons.

High efficiency coupling of radio frequency beams from the dual frequency gyrotron with a corrugated waveguide transmission system

High efficiency coupling of the millimeter-wave output of the dual-frequency gyrotron with the transmission line was demonstrated. The dual-frequency gyrotron was design to produce similar beam profiles for two operation frequencies (170 GHz and 137 GHz). Using two RF beam reflecting mirrors in a matching optics unit (MOU), which are designed to transform the beam profile of the gyrotron output to the fundamental waveguide mode (HE(11) mode) at 170 GHz, high efficiency coupling was demonstrated for two frequencies. The measured mode purity of HE(11) mode was 96% at 170 GHz and 94% at 137 GHz operations with the identical mirrors at the fixed mirror position and angle. The results indicate that the significantly simple dual frequency system is realized by the gyrotron designed to output the similar beam profiles at different frequency operation.

Power Transfer Optimization for HF RFID Systems Working in Metallic Environments

Abstract In wireless systems, the power transfer efficiency is very important. Many systems are used in harsh environments and the signal transmitted can be drastically affected by these environments. HF RFID systems are widespread nowadays, in many domains, but the metallic environments are an impediment to the extension of these systems in different applications. In this paper is presented a solution in optimizing the power transferred through the RFID reader antenna in the identification area where tags are found. This solution involves using an automatic matching unit (AMU) circuit that can match the impedance of the reader antenna at 50 Ω, even if the metallic environments located nearby are constantly changing. Using the proposed solution and only 1cm between the reader antenna and a metallic plane the reading distance is increased up to 75% from the reference distance (reading distance when no perturbing environment is used around). The fast tuning process can identify the tags even if they are attached by moving objects.

SIMULATION OF WAVEGUIDE TURNSTILE‐TYPE JUNCTION WITH A SQUARE WAVEGUIDE OUTPUT FOR INCOHERENT SCATTER RADAR ANTENNA

The computer simulation of the turnstile connection with a square waveguide output has been carried out. The matching unit dimensions have been optimized, and the main characteristics have been obtained. The use of the connection as a polarizer and antenna switch for incoherent radar is proposed.

Allele Matching At HLA-C or DRB1 Is Associated with Improved Survival After Reduced Intensity Double Umbilical Cord Blood Transplantation

Abstract 2010▪▪This icon denotes a clinically relevant abstractMismatch at HLA-C has been associated with increased transplant-related mortality in unrelated bone marrow and peripheral blood stem cell transplantation as well as single myeloablative umbilical cord blood transplantation (UCBT) in children, but the impact of HLA-C mismatch in adult double reduced-intensity conditioning (RIC) UCBT is unknown. Matching at HLA-C is not routinely considered in cord unit selection. We studied the effect of HLA-C matching in 125 patients who underwent double UCBT for hematologic malignancy at Dana-Farber Cancer Institute and Massachusetts General Hospital from 2003 through 2010. The median age was 49 years (range 16–69), and the diagnoses included acute leukemia (45%), MDS (12%), lymphoma (27%), myeloproliferative neoplasms (2%), and others (13%). Data on HLA-C match were recorded but not used in the UCB unit selection strategy. UCB unit selection criteria were a 4/6 allele level A, B, DR match with the patient and other UCB unit. 82% of patients received a fludarabine/melphalan/antithymocyte globulin RIC, and 62% received sirolimus-based graft vs host disease (GVHD) prophylaxis. The median follow-up time among survivors was 32 months (range 6–73). The degree of allele matching at HLA-C (donor to both cords) was 0/4 in 14 patients (11%), 1/4 in 21 patients (17%), 2/4 in 62 patients (50%), 3/4 in 20 patients (16%), and 4/4 in 8 patients(6.4%). Patients who received 2 UCB units both with > 6/8 match at HLA-A,-B,-C, and -DRB1 had improved survival (3 year overall survival (OS) 56% vs 29%, p= 0.01). There was a significant correlation between degree of matching at HLA-C and the frequency of neutrophil engraftment (ANC > 500 by day 42) (0/4=79%, 1/4=76%, 2/4=71%, 3/4=80%, 4/4=100%; p=0.004). Similarly, matching at HLA-C was significantly correlated with platelet engraftment (plt>20,000 by day 100) (0/4=50%, 1/4=52%, 2/4=57%, 3/4=70%, 4/4=100%; p=0.0004). Matching at HLA-A,-B, or –DRB1 did not correlate with engraftment. There was no effect of matching at HLA-C on relapse, acute GVHD, or chronic GVHD. A full match at HLA-C (4 alleles) was associated with improved survival (3-year OS 67% vs 33% with less than full match, p=0.05) but there only 8 patients who received 2 HLA-C matched UCB units. Degree of match individually at HLA-A,-B, or DRB1 was not alone associated with survival. When various combinations of match were examined, full matching at either HLA-C or full matching at HLA-DRB1 (with less than full matching at HLA-C), compared to full matching at neither locus, was associated with improved 3-year OS (67% vs. 42% vs. 24%, p=0.03). HLA-C match did not predict the dominant UCB unit. In summary, (1) patients who received closer HLA allele-level matched UCB units had improved survival after RIC double UCBT; (2) matching at HLA-C in RIC double UCBT may be associated with earlier neutrophil and platelet engraftment; (3) survival may be improved when patients received UCB units fully matched at HLA-C or fully matched at HLA-DRB1 (if less than fully matched at HLA-C) compared to recipients of units fully matched at neither locus; and (4) matching at HLA-A,-B, or DRB1 alone did not correlate with differences in engraftment or survival. These data are limited by the small number of patients that were compatible at HLA-C but warrant examination in a larger cohort to determine the role of matching at HLA-C in UCB unit selection algorithms. Disclosures:Soiffer:Genzyme: Consultancy; Fresenius biotech: Research Funding; Miltenyi Biotech: Consultancy.

Impact of Umbilical Cord Blood (UCB) T Regulatory Cells (Tregs) On Infection Risk Early After UCB Transplant

AbstractAbstract 4188We have previously shown that the infusion of ex vivo expanded UCB-derived Tregs at a dose of ≥3 × 106/kg immediately after UCB transplantation is associated with a reduced incidence of acute GVHD as compared to historical controls (p=0.05, Blood 2011; 117:1061). Together with a trend toward increased dual chimerism, these data support the conclusion that UCB Tregs are functional in vivo. We therefore asked the question whether Treg increased the increase risk of opportunistic infection (OI), particularly in the early transplant period when Treg are detectable in the peripheral blood. Opportunistic infections were defined as viral or fungal infections that were either documented or sufficiently supported by radiographic studies. For this analysis, patients receiving UCB-Tregs (n=24) were compared to historical controls (n=65) treated the same but without Tregs. All patients received a nonmyeloablative conditioning consisting of cyclophosphamide 50mg/kg/x1day, fludarabine 40 mg/m2/x5d, and total body irradiation 200 cGy/x1d and posttransplant immunosuppression consisting of mycophenate mofetil in combination with cyclosporine A (CsA, n=17 Treg patients and all controls) or sirolimus (n=7 Treg patients). Tregs were initially enriched by CD25+ selection (Miltenyi CliniMACS) from a partially HLA matched 3rd UCB unit Tregs were activated and expanded for 18+1 days in the presence of anti-CD3/CD28 mAb coated beads and rhIL-2. 90% of patients received one or two doses of 3 × 106/kg on d+1 (dose 1) and d+15 (dose 2) after UCB transplant. The median follow up of survivors is 2.6 (2.0–3.3) years and 4.8 (2.0–6.9) years for Treg and control patients, respectively. For non-Treg and Treg groups, the incidence of OI at day +100 was 58% (95%CI, 38–79%) and 57% (95%CI, 43–70%), respectively (p=0.74) at a median of 28 (21–87) and 41 (1–82) days after UCBT. Viral infections represented the majority of OI observed for Treg (58% [95%CI, 38–79%]) and non-Treg (55% [95%CI, 42–69%]) patient populations (p=.67). The overall day 0 to day +180 cumulative density of OI was 2.10 infections/1000 patient-days in Treg versus 1.52 infections/1000 patient-days in non-Treg patients (RR 1.39, p=.08). Notably, there was increased density of OI through day +30 with 18.06 infections/1000 patient-days for Treg patients versus 7.71 infections/1000 patient-days (RR 5.35, p=.02). In contrast, between day +31 and +180, the density of infection in Treg vs non-Treg patients was 4.22/1000 patient-days versus 7.22/1000 patient-days (RR 0.58, p=.07), respectively. The predominant viral infection observed in Treg patients through day +30 was HHSV-6 (n=9) with only two cases of CMV viremia and one case of parainflunenza upper respiratory infection). Despite the increased risk of early viral infections among Treg recipients, treatment related mortality at 1 year (18% vs. 10 %, p=0.36) and disease free survival at 2 years (33% vs. 34%, p=.95) were similar compared to historical controls. Interestingly, of the 7 recipients of Treg in the presence of sirolimus, none developed OI and 5/7 are alive. In conclusion, there is an increased risk of OI early after transplant in recipients of UCB Tregs and posttransplant pharmacological immunosuppression. Whether higher or multiple Treg doses may be more effective in suppressing acute GVHD, OI risk may be increased especially when used in combination with CsA. A dose escalation study UCB-derived Tregs expanded with KT86/64 artificial antigen presenting cells in the presence of sirolimus/MMF immune suppression is underway. Disclosures:Miller:Celgene: Membership on an entity's Board of Directors or advisory committees; Coronado Bioscience: Membership on an entity's Board of Directors or advisory committees.

Evaluation of Balanced Capacitance Matching Unit for HF RFID Systems in Metallic Environments

RFID systems are sensitive to metallic environments in the proximity of the reader antenna. These influences produce shifting of the resonance frequency, causing performances degradation for the entire RFID system. Based on the behavior analysis of an HF RFID antenna circuit in the proximity of metallic environments, in this paper are proposed two tuning methods using a simplistic approach and some mathematical determinations. These solutions can be taken into account when it’s necessary to implement a HF RFID system that can offer good performances even if the metallic environments in the proximity of the antenna are constantly changing.DOI: http://dx.doi.org/10.5755/j01.eee.18.9.2803

Hematopoietic Cell Transplantation with Cord Blood for Cure of HIV Infections

Hematopoietic cell transplantation (HCT) using CCR5-Δ32/Δ32 stem cells from an adult donor has resulted in the only known cure of human immunodeficiency virus (HIV) infection. However, it is not feasible to repeat this procedure except rarely because of the low incidence of the CCR5-Δ32 allele, the availability of only a small number of potential donors for most patients, and the need for a very close human leukocyte antigen (HLA) match between adult donors and recipients. In contrast, cord blood (CB) transplantations require significantly less stringent HLA matching. Therefore, our hypothesis is that cure of HIV infections by HCT can be accomplished much more readily using umbilical CB stem cells obtained from a modestly sized inventory of cryopreserved CCR5-Δ32/Δ32 CB units. To test this hypothesis, we developed a screening program for CB units and are developing an inventory of CCR5-Δ32/Δ32 cryopreserved units available for HCT. Three hundred such units are projected to provide for white pediatric patients a 73.6% probability of finding an adequately HLA matched unit with a cell dose of ≥2.5 × 107 total nucleated cells (TNCs)/kg and a 27.9% probability for white adults. With a cell dose of ≥1 × 107 TNCs/kg, the corresponding projected probabilities are 85.6% and 82.1%. The projected probabilities are lower for ethnic minorities. Impetus for using CB HCT was provided by a transplantation of an adult with acute myelogenous leukemia who was not HIV infected. The HCT was performed with a CCR5-Δ32/Δ32 CB unit, and posttransplantation in vitro studies indicated that the patient's peripheral blood mononuclear cells were resistant to HIV infection.

MONITORING POWER CONSUMPTION USING A GENERALIZED VARIANT OF SELF-ORGANIZING MAP (SOM)

In this paper, we present a new approach for monitoring power consumption in several processes. The generalization of the envSOM algorithm, a variant of Self-Organizing Map (SOM), is used to build an electrical model and visualize the information. The envSOM extended to n hierarchical phases allows us to obtain a more accurate model from real past data. The model is conditioned hierarchically on environmental variables. In this way, time variables can be used to consider seasonality and weekday/hour periodicity. Time variable maps and electrical component planes make it possible to visualize and analyze power consumption. The representation of the Best Matching Unit (BMU) or its trajectory on these maps enables the on-line monitoring.

122-P

Aim Current practice for identifying a suitable 4/6 matched CBU is antigen level matching at HLA-A and B and allele level matching at HLA-DRB1, while matching at HLA-C is not typically considered. Recent studies have suggested that matching at HLA-C may improve transplant related mortality (Eapen et al., 2011). Determining the availability of a suitably matched (x/8) CBU is important for potentially improving transplant related outcomes for patients. Methods We examined a cohort of single CBU transplants from December to February 2012 to determine if a better matched (antigen level at HLA-A, B, C and allele level at HLA-DRB1, x/8) unit was available in the Be The Match Registry®. The better matched unit had to retain the traditional 4/6 or better match category (MC) and a minimum cell dose of 2.5 × 107 TNC/kg or no lower than the selected unit TNC. CBU without HLA-C typing were considered matched if algorithm predictions were ⩾50%. Results 119 single CBU transplant cases were assessed. 79 (66%) of these cases selected the best matched unit. 40 (34%) had a better matched x/8 unit available, where 36 (90%) improved one MC (x/8) and four cases (10%) improved two MCs. The cell dose of the better matched unit was lower in 57.5% of cases, with the median change in cell dose of −9.3%. Conclusions The benefit of HLA-C matching for CBU transplant has not been fully elucidated. This analysis highlights that although current practice may not always consider HLA-C matching, often a similar or better matched unit is available including HLA-C. This study cannot account for the myriad of factors considered in CBU selection such as cell dose, mismatching at a particular locus (e.g. HLA-DRB1), previous confirmatory typing, patient antibodies, CBU protocols or physician preference. These data indicate that when solely considering HLA matching in CBU selection, units that also matched at the C locus while maintaining similar unit cell dose were available.

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Aim Umbilical Cord Blood is validated as an alternative stem cell source allowing less HLA restriction for patients with malignant diseases. Besides the classical HLA matching, KIR genes form an independent diverse immunogenetic system that seems to have a significant influence on the outcome of allogeneic HSCT, especially the presence of B genotypes in the donor. Thus, the question rises on the possible value of KIR genotyping of prospective donors as an additional selection criterion. The aim of this study was to examine the diversity of the KIR repertoire of the HCBB (Hellenic Cord Blood Bank) inventory in comparison to previously documented favorable gene content (Cooley et al, 2010). Methods For this reason KIR genotyping of 320 CBU, for the presence of 14 KIR genes was performed, by PCR-SSO/SSP. Results The results revealed that 72.8% (233/320) of the donors had a Bx KIR genotype, while the remainder had the AA, which agreed with previously published KIR haplotype frequencies of the Greek population. When Bx KIR genotype content was further analyzed, 82.4% (192/233) of the CBUs had both KIR 2DL2/2DS2 (which may be independently advantageous), while 17.6% (41/233) had neither. On the other hand, the great variability of Bx genotypes observed in our inventory, indicates that units could be classified on the basis of a KIR B content score, in order to find a matching unit with the most favorable KIR gene content for a given patient. Conclusions In conclusion, adopting KIR genotyping could maximize the chance of identifying the optimal unit, out of several HLA-matched CBUs in our inventory, and would also be very attractive to incorporate in a unit selection algorithm in the future. It could become an additional service offered by the HCBB, which already offers high quality units that meet the highest standards in regards to TNC dose, CD34+ and CFU counts, HLA typing for HLA-A,-B,-DRB1 of both CBUs and mothers (making matching for NIMAs possible) and undergo all the required testing.

Self organising maps for visualising and modelling

The paper describes the motivation of SOMs (Self Organising Maps) and how they are generally more accessible due to the wider available modern, more powerful, cost-effective computers. Their advantages compared to Principal Components Analysis and Partial Least Squares are discussed. These allow application to non-linear data, are not so dependent on least squares solutions, normality of errors and less influenced by outliers. In addition there are a wide variety of intuitive methods for visualisation that allow full use of the map space. Modern problems in analytical chemistry include applications to cultural heritage studies, environmental, metabolomic and biological problems result in complex datasets. Methods for visualising maps are described including best matching units, hit histograms, unified distance matrices and component planes. Supervised SOMs for classification including multifactor data and variable selection are discussed as is their use in Quality Control. The paper is illustrated using four case studies, namely the Near Infrared of food, the thermal analysis of polymers, metabolomic analysis of saliva using NMR, and on-line HPLC for pharmaceutical process monitoring.

Why are thoracic operations postponed?

AimTo investigate and present the reasons that cause the postponement of thoracic surgical operations.MethodsWe retrospectively included in the study all patients submitted to elective thoracic surgery in our department during the 4-year period 2007-2010 and noted all cases of postponement after official inclusion in the operating schedule.Results81 out of a total of 542 patients (14.9%) scheduled for elective thoracic operation had their procedure postponed. The reasons were mainly organisatory (in 42 cases, 51.85%), which in order of significance were: shortage in matching erythrocyte units, shortage in anaesthetic/nursing staff and unavailability in operating rooms. The rest of the cases (39, 48.1%) were postponed due to medical reasons, which in descending order of significance were: respiratory infections and exacerbations of COPD, cardiological problems, misregulation of antiplatelet/antithrombotic drugs and infections from other systems (gastrointestinal, urinary, etc.). Elderly male patients planned for major/oncologic surgery were most possible to have their operation postponed for medical reasons.Discussion-ConclusionsThoracic operations are postponed owed to organisatory as well as medical reasons, the latter mainly affecting elderly, morbid patients awaiting for major/oncologic surgery.

Cord blood banking activities at a university hospital in northeast Mexico: an 8‐year experience

Umbilical cord blood (UCB) represents an alternative source of stem cells for transplantation for the treatment of hematologic malignancies and genetic disorders. There is scarce information detailing cord blood bank (CBB) collection and transplantation activities from developing countries. We documented our experience at a public university hospital in northeast Mexico. We carried out a retrospective and descriptive analysis of our CBB activity during an 8-year period from May 2002 to September 2010. Collection, processing, and cryopreservation of CB were carried out following standard operating procedures. The minimum volume and total nucleated cell (TNC) content for cryopreservation were 80 mL and 8.0 × 10(8) , respectively. A total of 1256 UCB units were collected; 428 (34%) were banked and 828 (66%) were discarded. The main reason for exclusion was biologic: low volume and/or low number of TNC accounted for 84% of the total discarded units. Cryopreserved cord blood units (CBUs) had a median volume of 113.8 mL (range, 80-213.2 mL) and 13.0 × 10(8) (range, 8 × 10(8) -36.6 × 10(8) ) TNCs. Cell viability was 99.3% (88-100%). The median CD34+ cell content was 4.0 × 10(6) (0.46 × 10(6) -19.38 × 10(6) ). Sixteen units have been released for transplantation, leading to a utilization rate of 3.7%. CBB demands considerable human and financial resources; it is then essential for centers at developing countries to share their experience, results, and databases to increase the probability of finding matching units for their patients. Efforts to create and maintain CBBs allow to offer this therapeutic option at an affordable cost.

A Method for Gyrotron Beam Coupling into a Corrugated Waveguide

In the radio-frequency (rf) power transmission system of an electron cyclotron heating and current drive (EC H&CD) system, the gyrotron power should couple with the fundamental mode of the corrugated waveguide (HE11 mode) because unwanted higher-order modes affect the beam radiation characteristics, which is a problem in the quasi-optical launcher design. To achieve high HE11 mode purity, a beam coupling method that measures the transmission mode in the waveguide was examined using a 170-GHz high-power gyrotron for the first time. In beam coupling, the offset and tilt angle of the input beam at the waveguide inlet were minimized by controlling the angles of the mirrors in the matching optical unit (MOU) to minimize unwanted LP11 modes in the waveguide. The rf field profile in free space after 1.3 m of the waveguide from the MOU was measured, and the transmission mode content was analyzed. According to the analyzed mode content, the HE11 mode content was optimized by remote adjustment of the mirror angles with a digital controller. The optimization procedure of beam coupling achieved 95% of HE11 mode purity at the entrance of transmission line, which is the first demonstration that meets the criteria of the ITER EC H&CD system.

Visual query processing for efficient image retrieval using a SOM-based filter-refinement scheme

Visual query processing is one of the new issues for content-based image retrieval. In this paper, we propose (i) a filter-refinement scheme based on a modified form of the self-organizing map and (ii) a new interactive approach for similarity matching in image retrieval based on visual query processing. Specifically, we first propose a new local membership function, which preserves the relationships between the input feature vectors of the images and their neighboring weight vectors, to project the high dimensional input feature vectors to a low dimensional grid. Then, all the input feature vectors are mapped and visualized in the 2D grid. The feature vector of the query image is mapped and visualized in the 2D grid as well. The users not only can visualize the locations of the query image and the image data in the database, but also visualize the locations of the relevant and irrelevant images. Next, the users retrieve the candidates from the 2D grid interactively through visual query processing in the filter phase. Finally, the query results are obtained from the candidates by performing similarity ranking in the original feature space during the refinement phase. In order to accelerate the query process, we use a hierarchical tree to index the weight vectors of the self-organizing map (SOM) units to reduce the computation cost for finding the best matching unit. Our experiments show that (i) the proposed approach works well on both synthetic datasets and image data, (ii) the proposed visual query processing approach is more efficient than conventional approaches and can enhance the overall interactive experience through fast feedback, and (iii) the filter-refinement scheme makes our proposed approach more robust than conventional approaches.