An Approximation Algorithm for Two-Edge-Connected Subgraph Problem via Triangle-free Two-Edge-Cover

The $2$-Edge-Connected Spanning Subgraph problem (2-ECSS) is one of the most fundamental and well-studied problems in the context of network design. In the problem, we are given an undirected graph $G$, and the objective is to find a $2$-edge-connected spanning subgraph $H$ of $G$ with the minimum number of edges. For this problem, a lot of approximation algorithms have been proposed in the literature. In particular, very recently, Garg, Grandoni, and Ameli gave an approximation algorithm for 2-ECSS with factor $1.326$, which was the best approximation ratio. In this paper, we give a $(1.3+\varepsilon)$-approximation algorithm for 2-ECSS, where $\varepsilon$ is an arbitrary positive fixed constant, which improves the previously known best approximation ratio. In our algorithm, we compute a minimum triangle-free $2$-edge-cover in $G$ with the aid of the algorithm for finding a maximum triangle-free $2$-matching given by Hartvigsen. Then, with the obtained triangle-free $2$-edge-cover, we apply the arguments by Garg, Grandoni, and Ameli

A fundamental study assessing the generalized fitting method in conjunction with every possible coalition of N-combinations (G-EPOC) using the appendicitis detection task of computed tomography

Purpose: Increased use of deep learning (DL) in medical imaging diagnoses has led to more frequent use of 10-fold cross-validation (10-CV) for the evaluation of the performance of DL. To eliminate some of the (10-fold) repetitive processing in 10-CV, we proposed a "generalized fitting method in conjunction with every possible coalition of N-combinations (G-EPOC)", to estimate the range of the mean accuracy of 10-CV using less than 10 results of 10-CV. Material and methods: G-EPOC was executed as follows. We first provided (2N-1) coalition subsets using a specified N, which was 9 or less, out of 10 result datasets of 10-CV. We then obtained the estimation range of the accuracy by applying those subsets to the distribution fitting twice using a combination of normal, binominal, or Poisson distributions. Using datasets of 10-CVs acquired from the practical detection task of the appendicitis on CT by DL, we scored the estimation success rates if the range provided by G-EPOC included the true accuracy. Results: G-EPOC successfully estimated the range of the mean accuracy by 10-CV at over 95% rates for datasets with N assigned as 2 to 9. Conclusions: G-EPOC will help lessen the consumption of time and computer resources in the development of computer-based diagnoses in medical imaging and could become an option for the selection of a reasonable K value in K-CV

Measurement of Secondary Products During Oxidation Reactions of Terpenes and Ozone Based on the PTR-MS Analysis: Effects of Coexistent Carbonyl Compounds

Continuous measurements using proton transfer reaction mass spectrometry (PTR-MS) can be used to describe the production processes of secondary products during ozone induced oxidation of terpenes. Terpenes are emitted from woody building materials, and ozone is generated from ozone air purifiers and copy machines in indoor environments. Carbonyl compounds (CCs) are emitted by human activities such as smoking and drinking alcohol. Moreover, CCs are generated during ozone oxidation of terpenes. Therefore, coexistent CCs should affect the ozone oxidation. This study has focused on the measurement of secondary products during the ozone oxidation of terpenes based on the use of PTR-MS analysis and effects of coexistent CCs on oxidized products. Experiments were performed in a fluoroplastic bag containing α-pinene or limonene as terpenes, ozone and acetaldehyde or formaldehyde as coexistent CCs adjusted to predetermined concentrations. Continuous measurements by PTR-MS were conducted after mixing of terpenes, ozone and CCs, and time changes of volatile organic compounds (VOCs) concentrations were monitored. Results showed that, high-molecular weight intermediates disappeared gradually with elapsed time, though the production of high-molecular weight intermediates was observed at the beginning. This phenomenon suggested that the ozone oxidation of terpenes generated ultrafine particles. Coexistent CCs affected the ozone oxidation of α-pinene more than limonene

Dynamic effects of the Nuss procedure on the spine in asymmetric pectus excavatum

ObjectiveThis study aimed to elucidate dynamic effects of the Nuss procedure on the spine in the treatment of patients with pectus excavatum with asymmetric thoraces.MethodsTwenty-five patients with pectus excavatum who underwent the Nuss procedure were categorized into 4 groups by preoperative morphology of the spine and thoracic asymmetry. In group 1 (n = 8), the right side of the thorax was concave and the spine bowed to the right. In group 2 (n = 4), the right side of the thorax was concave and the spine bowed to the left. In group 3 (n = 5), the left side of the thorax was concave and the spine bowed to the right. In group 4 (n = 8), the left side of the thorax was concave and the spine bowed to the left. With computed tomographic data, finite-element models were produced to simulate each patient's thorax. Thereafter, dynamic response patterns of the spine to the Nuss procedure were examined. Validity of these biomechanical findings was verified by referring to clinical outcomes.ResultsIn group 1 and group 4 models, deformed spines were straightened; in group 2 and group 3 models, spinal bowing increased. These biomechanical findings were compatible with clinical evaluations.ConclusionsPerformance of the Nuss procedure for asymmetric pectus excavatum exerts dynamic influence on the spine. Response patterns of the spine are predictable from morphologic relationships between the asymmetric patterns of the anterior thoracic wall and the spine

Improvement of dynamic characteristics of manipulator driven by a gas-liquid phase-change actuator using an antagonistic drive

The goal of this research is to improve the dynamic characteristics of a manipulator composed of pneumatic artificial rubber muscles driven by gas-liquid phase change. Pneumatic actuators, such as pneumatic artificial rubber muscle (PARM) or rubber bellows, have been widely used in many industrial and research fields. They have merits of being compact and lightweight. However, the large size of the compressor driving the actuator is a problem. To overcome this, the authors researched soft actuators driven by the gas-liquid phase change (GLPC) of fluorocarbon. Fluorocarbon (C5F11NO) is a substance with a relatively low boiling point (50 °C) and a low heat of evaporation (104.65 kJ/kg). The heat of evaporation of water is 2260 kJ/kg. This paper presents the overview of an actuator driven by GLPC. Then, fabrication of a manipulator using the GLPC driven PARM, and details of experiments conducted to determine manipulator characteristics are given. To improve the dynamic characteristics of the manipulator, a force control method using the antagonistic drive of two PARMs is proposed, and experiments are conducted to validate the effectiveness of the proposed method

Three-dimensional object profiling using highly accurate FMCW optical ranging system

金沢大学理工研究域フロンティア工学系We have developed three-dimensional object profiling system using a highly accurate frequency-modulated continuous-wave optical ranging system. A DFB laser and a vertical-cavity surface-emitting laser (VCSEL) are used as the laser source and the optical frequency is swept by the injection current modulation with a symmetric triangular wave. The influence of nonlinearity in the optical frequency sweep is canceled by utilizing k-sampling technique. Since the optical frequency sweep range of a VCSEL is larger than that of a DFB laser, high spatial resolution and high ranging accuracy are achieved by using a VCSEL. The spatial resolution evaluated by the full-width at half-maximum (FWHM) is 460 μm and the standard deviation of the ranging accuracy is σ = 2.7, μm when a VCSEL is used as the frequency-swept laser source, and the FWHM is 2.3 mm and σ = 14.8 μ m when a DFB laser is used as the frequency-swept laser source. Accordingly, fine and clear object profiling of a coin and a printed circuit board is achieved by using a VCSEL as the frequency-swept laser source. Finally, we speed up the measurement time by increasing the repetition frequency of the injection current modulation and optimizing timing of the data acquisition, the galvano mirror scan and the fast Fourier transform analysis by taking account of the transient response of the galvano mirror, and the fastest measurement time of 22.6 s is achieved for 201 × 201 measurement points, which is four times faster than our previous results. We also discuss the effect of moving average filtering and median filtering to improve profiling quality

High speed measurement for object profiling using FMCW optical sensing system

金沢大学理工研究域フロンティア工学系A sensor that is beneficial to inspect small devices has been missing in life science as well as industry. Frequency modulated continuous wave (FMCW) optical sensing system has been successful in profiling the image of a coin and a printed circuit board with the measurement accuracy of 3σ = 29 µm in 10 minutes by using a DFB laser. Here we propose and demonstrate a faster profiling system using a VCSEL. We applied three conditions for high-speed FMCW optical sensing system, i.e. symmetric method with the different modulation frequency, modulation amplitude, and asymmetric method. The results show that asymmetric method is successful in profiling a coin object with a diameter of 2.25 cm in 23.13 seconds.International Symposium on Frontier of Applied Physic

Metastatic Renal Cell Carcinoma to the Left Sphenoid Sinus: A Case Report in Light of the Literature

A 79-year-old Japanese woman presented with a rare case of metastatic renal cell carcinoma to the left sphenoid sinus with left nasal bleeding. She had previously had right radical nephrectomy for renal cell carcinoma at the age of 64 years and brain and spinal cord infarction at 74 years. Endoscopic examination revealed no mass in the nasal cavity. CT and MRI revealed a tumor in the left sphenoid sinus. The size of the tumor increased gradually from 12 to 15 years after the radical nephrectomy. Complete resection with endoscopic surgery was performed without preoperative embolization. The tumor cells had clear cytoplasm and were arranged in a trabecular pattern lined by a layer of endothelial cells. These findings were identical to the pathological findings of the surgical specimen of the renal cell carcinoma from 15 years previous. A pathological diagnosis of metastatic renal cell carcinoma of clear cell type (grade 1) was made. PET-CT demonstrated no metastasis. The patient’s condition was successfully managed with excision of the tumor, and she remains well with no evidence of recurrence and metastasis 36 months after treatment. Metastatic renal cell carcinoma to the sphenoid sinus is rare, but it might be considered in the differential diagnosis of masses in the paranasal sinus even long after initial treatment of renal cancer

World Robot Challenge 2020 -- Partner Robot: A Data-Driven Approach for Room Tidying with Mobile Manipulator

Tidying up a household environment using a mobile manipulator poses various challenges in robotics, such as adaptation to large real-world environmental variations, and safe and robust deployment in the presence of humans.The Partner Robot Challenge in World Robot Challenge (WRC) 2020, a global competition held in September 2021, benchmarked tidying tasks in the real home environments, and importantly, tested for full system performances.For this challenge, we developed an entire household service robot system, which leverages a data-driven approach to adapt to numerous edge cases that occur during the execution, instead of classical manual pre-programmed solutions. In this paper, we describe the core ingredients of the proposed robot system, including visual recognition, object manipulation, and motion planning. Our robot system won the second prize, verifying the effectiveness and potential of data-driven robot systems for mobile manipulation in home environments