Point Cloud Clustering Using Panoramic Layered Range Image

Point-cloud clustering is an essential technique for modeling massive point clouds acquired with a laser scanner. There are three clustering approaches in point-cloud clustering, namely model-based clustering, edge-based clustering, and region-based clustering. In geoinformatics, edge-based and region-based clustering are often applied for the modeling of buildings and roads. These approaches use low-resolution point-cloud data that consist of tens of points or several hundred points per m2, such as aerial laser scanning data and vehicle-borne mobile mapping system data. These approaches also focus on geometrical knowledge and restrictions. We focused on region-based point-cloud clustering to improve 3D visualization and modeling using massive point clouds. We proposed a point-cloud clustering methodology and point-cloud filtering on a multilayered panoramic range image. A point-based rendering approach was applied for the range image generation using a massive point cloud. Moreover, we conducted three experiments to verify our methodology

Supersonic nozzle flow in the two-phase ejector as water refrigeration system by using waste heat

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.In the near future the usage of waste heat in houses will be increased. The development of refrigeration system using waste heat is particularly needed for summer season consumptions. The ejector cycle can directly convert the thermal energy into the compression mechanical energy. Moreover, water which is one of the cleanest refrigerants can be used in the ejector cycle. As the steam ejector has been researched [1-3] as air conditioning system, the huge energy needed for large latent heat for water. We propose that the high-speed steam and water mixture, so-called two-phase flow, can be utilized instead of steam. It is theoretically shown that the heat need for this system will be reduced by the latent heat of hot water in two-phase flow, if the two-phase in the ejector flow has the same potential of acceleration and compression as steam. And the nozzle efficiencies for the two-phase flow of water are also obtained by the experiment

Experimental research on the two-phase flow nozzle performance of the ejector for carbon dioxide

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Natural refrigerant such as carbon dioxide which is a safe refrigerant without toxicity and flammability attracts attention from a viewpoint of environmental load-reducing. However, the energy loss at the expansion valve in carbon dioxide refrigerant cycle is three times larger than that of the usual cycle using refrigerant R-134a. The two-phase ejector is one of those devices which improve Coefficient Of Performance (COP) by using the expansion energy of the refrigerant. The object of the present paper is to elucidate the twophase flow nozzle performance of carbon dioxide from the experiment using the precise measurement of the pressure along the nozzle. It is found by the present experiment that the maximum energy conversion efficiency of two-phase flow nozzle for carbon dioxide is about the order of 95%. The experimental results show that there is some suitable length in divergent section of two-phase flow nozzle. In the shortest nozzle, the pressure decreases from the saturation are measured at the nozzle throat because of requirements for large superheat of liquid refrigerants. Those experimental results will be utilized for the design of the two-phase flow ejector using carbon dioxide as a refrigerant.dc201

Investigation on oblique shock waves occurred in the supersonic carbon dioxide two-phase flow

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.In the refrigeration systems using the two-phase flow ejector, it is important to understand expansion waves and shock waves which are generated at the outlet of the nozzle. The theoretical oblique shock wave relations are derived for extreme conditions. Numerical analysis of the oblique twophase flow is also presented. Two types of two dimensional convergent-divergent nozzles with and without the inclined wall are used to measure pressure profiles along the nozzles wall. The two-phase flow in the divergent section of the nozzle obviously exhibits the supersonic decompression behavior. Numerical results can represent the experimental results with fairly good precision, but the reflections of the oblique shock wave cannot be predicted. The diameter of the droplet in twophase flow in the nozzle is guessed by this experiment to be the order of 5 [μm] and momentum frozen phenomenon occurs in this situation. The experimental oblique shock wave has the particular character of the two-phase flow, which is never seen in single phase flow explained by gas dynamics. The observation of the present study reveals the intrinsic feature that appears only in the supersonic two-phase flow.dc201

Outer retinal circular structures in patients with Bietti crystalline retinopathy.

[Background] : Bietti crystalline retinopathy (BCR) is a distinct retinal degenerative disease characterised by retinal degeneration with many yellow–white crystals located mainly at the posterior pole area. Using spectral domain-optical coherence tomography (SD-OCT), the structural change in retina was investigated. [Methods] : Patients diagnosed with BCR (n=12), retinitis pigmentosa (RP, n=292) and cone dystrophy (n=16) were included in this study. The authors mainly examined fundus photographs and SD-OCT, infrared and fundus autofluorescence images of these patients. [Results]: Crystalline deposits were detected in portions of the retinal pigment epithelium that lacked patchy degenerated lesions. SD-OCT revealed that most of the observed crystalline deposits were located adjacent to the inner side of retinal pigment epithelium layer. The change most frequently observed was circular hyper-refractive structures in the outer nuclear layer. Although the structures were considered to be previously reported “tubular formation” or “tubular degeneration”, we determined that many of these circular structures were slices of spherical structures and were typically noted in areas suspected of ongoing active degeneration. [Conclusion] : BCR has characteristic structures in the outer nuclear layer. Although the incidence of the structure varies, it may be characteristic of retinal degeneration and can be found in many retinal degenerative diseases

Disease-Free Interval Length Correlates to Prognosis of Patients Who Underwent Metastasectomy for Esophageal Lung Metastases

BackgroundPulmonary metastasectomy is a standard method for treatment of selected pulmonary metastases cases. Nevertheless, because prognosis for patients with lung metastases from esophageal cancer who have undergone pulmonary metastasectomy is poor, candidates for this method of treatment are rare. Therefore, the efficacy of surgical treatment for pulmonary metastatic lesions from esophageal cancer has not been thoroughly examined.MethodsBetween March 1984 and May 2006, 57 patients underwent resection of pulmonary metastases from primary esophageal cancer. These cases were registered in the database developed by the Metastatic Lung Tumor Study Group of Japan and were retrospectively reviewed from the registry. After excluding eight cases because of missing information, we reviewed the remaining 49 cases and examined the prognostic factors for pulmonary metastasectomy for metastases from esophageal cancer.ResultsThere were no perioperative deaths. After pulmonary metastasectomy, disease recurred in 16 (33%) of the 49 patients. The overall 5-year survival was 29.6%. Median survival time was 18 months. The survival of patients with a disease-free interval (DFI) less than 12 months was significantly lower than patients with a DFI greater than 12 months. Through multivariate analysis, we identified DFI as a clinical factor significantly related to overall survival (p = 0.04).ConclusionsWe identified that patients with a DFI less than 12 months who underwent pulmonary metastasectomy for metastases from esophageal cancer had a worse prognosis. Pulmonary metastasectomy for esophageal cancer should be considered for selected patients with a DFI ≥12 months

Topology optimization of damping material for reducing resonance response based on complex dynamic compliance

In this research, we propose a new objective function for optimizing damping materials to reduce the resonance peak response in the frequency response problem, which cannot be achieved using existing criteria. The dynamic compliance in the frequency response problem is formulated as the scalar product of the conjugate transpose of the amplitude vector and the force vector of the loading nodes. The proposed objective function methodology is implemented using the common solid isotropic material with penalization (SIMP) method for topology optimization. The optimization problem is formulated as maximizing the complex part of the proposed complex dynamic compliance under a volume constraint. 2D and 3D numerical examples of optimizing the distribution of the damping material on the host structure are provided to illustrate the validity and utility of the proposed methodology. In these numerical studies, the proposed objective function worked well for reducing the response peak in both lower and upper excitation frequencies around the resonance. By adjusting the excitation frequency, multi-resonance peak reduction may be achieved with a single frequency excitation optimization.This research was partially supported by JSPS KAKENHI Grant Numbers 25820422 and 25630436

Clinical characteristics and course of sporadic non-ampullary duodenal adenomas A multicenter retrospective study

Sporadic non-ampullary duodenal adenoma (SNADA) is a rare disease, and therefore, its clinical characteristics have not been comprehensively investigated. Furthermore, owing to the high complication rates and severity of endoscopic resection, treatment strategies vary among facilities. In the present study, we aimed to clarify the clinical characteristics and course of SNADA. We extracted clinical and histological records of SNADA cases diagnosed in 11 hospitals between September 1999 and August 2014. The patients were divided into "no-resection" and "resection" groups based on the initial treatment approach. We investigated the long-term outcome of the "no-resection" group and treatment results of the "resection" group, with particular interest in endoscopic resection. Overall, 299 patients were diagnosed with SNADA. The median age at diagnosis was 67 years (range, 31-88 years), with approximately twice as many men as women. The median tumor size was 8.0 mm (2-60 mm). In total, 161 patients were initially selected for no-resection and 138 underwent resection. Age >70 years and the presence of either severe illness or poor performance status were significantly related to opting for no-resection. In the no-resection group, 101 patients underwent endoscopic follow-up for at least 1 year. During the observational period (2.5 +/- 2.2 years), 27 lesions (27%) disappeared following cold forceps biopsy, and 13 lesions (14%) presented lateral growth. Four lesions (4%) changed to mucosal carcinoma, 3 were treated endoscopically, and 1 was surgically resected. Nineteen patients died; however, no one died of duodenal carcinoma. In the endoscopic resection group, en bloc resection was achieved in 78% of patients. However, the complication rate for perforation was 7%, and endoscopic submucosal dissection was associated with a 36% perforation rate. With the low incidence of cancer development and no disease specific death, the strategy of initially not performing resection could be considered especially for the older adults, poor-prognosis patients, or small lesions

An Evaluation of the Safety and Feasibility of Adenosine-assisted Clipping Surgery for Unruptured Cerebral Aneurysms: Study Protocol

The effectiveness of adenosine-induced flow arrest in surgical clipping for the cerebral aneurysms with difficulties in temporary clip placement to the proximal main trunk has been reported. This is the first clinical trial to evaluate the safety and feasibility of adenosine-assisted clipping surgery for unruptured cerebral aneurysms (UCAs) in Japan. The inclusion criteria are as follows: patients over 20 years old, patients who agree to be enrolled in this study after providing informed consent, patients who undergo clipping surgery for UCA in our institute, and patients in whom the surgeons (T.H. or I.D.) judge that decompression of the aneurysm is effective. The primary endpoint is a modified Rankin Scale (mRS) score 30 days after surgery. We plan to enroll 10 patients in this study. The original protocol of adenosine administration was established in this trial. Herein, we present the study protocol