Optimal design of the gerotor (2-ellipses) for reducing maximum contact stress

The oil pump, which is used as lubricator of engines and auto transmission, supplies working oil to the rotating elements to prevent wear. The gerotor pump is used widely in the automobile industry. When wear occurs due to contact between an inner rotor and an outer rotor, the efficiency of the gerotor pump decreases rapidly, and elastic deformation from the contacts also causes vibration and noise. This paper reports the optimal design of a gerotor with a 2-ellipses combined lobe shape that reduces the maximum contact stress. An automatic program was developed to calculate Hertzian contact stress of the gerotor using the Matlab and the effect of the design parameter on the maximum contact stress was analyzed. In addition, the method of theoretical analysis for obtaining the contact stress was verified by performing the fluid-structural coupled analysis using the commercial software, Ansys, considering both the driving force of the inner rotor and the fluid pressure, which is generated by working oil.

     

Modularizing services: A modified HoQ approach

Compared with manufacturing, the modularization of services has rarely been dealt with, despite its potential benefits. More specifically, the question of how to modularize services in the practical context is still an unexplored subject. In response, this paper proposes a solid framework for service modularization, by employing and modifying the House of Quality (HoQ) structure in Quality Function Deployment (QFD) using two ways: driver-based approach and interrelationship-based approach. Firstly, module drivers representing the service characteristics are identified through a comprehensive literature review. In this step, twofold module drivers are identified: one for common and the other for service-specific. Secondly, by considering the interdependent nature of service offering, service is decomposed according to the three predefined dimensions: service process, service outcome, and prerequisites for the service. Service modularization is then conducted using HoQ structure; the relationships between module drivers and decomposed service components are analyzed in the Strategic Modularability Matrix (SMM), whereas the interrelationships among service components are identified in Interrelated Components Modularability Matrix (ICMM). Finally, a clustering analysis is conducted to identify the module candidates. In order to illustrate the utility of the proposed approach, a restaurant service is exemplified. This study contributes to the field by filling the void left by the service sector by applying the service-specific module drivers to modularize services, as well as analyzing the relationship among service components using three interrelated dimensions.     

Quantification of the risk for hydrate formation during cool down in a dispersed oil-water system

Gas hydrates are considered a nuisance in the flow assurance of oil and gas production since they can block the flowlines, consequently leading to significant losses in production. Hydrate avoidance has been the traditional approach, but recently, hydrate management is gaining acceptance because the practice of hydrate avoidance has become more and more challenging. For better management of hydrate formation, we investigated the risk of hydrate formation based on the subcooling range in which hydrates form by associating low, medium, and high probability of formation for a gas+oil+water system. The results are based on batch experiments which were performed in an autoclave cell using a mixture gas (CH₄: C₃H₈=91.9 : 8.1 mol%), total liquid volume (200 ml), mineral oil, watercut (30%), and mixing speed (300 rpm). From the measurements of survival curves showing the minimum subcooling required before hydrate can form and hydrate conversion rates for the initial 20 minutes, we developed a risk map for hydrate formation.     

Robust mixed time-optimal control for third-order systems with model uncertainty

In this paper, a robust near time-optimal controller for some third-order uncertain systems with constrained input is presented. The response is usually composed of two parts. At first, the states move towards the goal state from arbitrary initial conditions by pure time-optimal control (bang-bang) and then there is sliding along a predetermined surface within an ellipsoid. The sliding surface is chosen in such a way that the integral of the absolute value of the system error is minimized. Using a combined control algorithm, robustness and stability of the system is guaranteed even with parameter uncertainty and disturbance. The error convergence rate is also improved compared with pure time-optimal control. Simulation results demonstrate the advanced performance of the proposed control algorithm.     

Online recognition of handwritten music symbols

In this paper, we propose an effective online method to recognize handwritten music symbols. Based on the fact that most music symbols can be regarded as combinations of several basic strokes, the proposed method first classifies all the strokes comprising an input symbol and then recognizes the symbol based on the results of stroke classification. For stroke classification, we propose to use three types of features, which are the size information, the histogram of directional movement angles, and the histogram of undirected movement angles. When combining classified strokes into a music symbol, we utilize their sizes and spatial relation together with their combination. The proposed method is evaluated using two datasets including HOMUS, one of the largest music symbol datasets. As a result, it achieves a significant improvements of about 10% in recognition rates compared to the state-of-the-art method for the datasets. This shows the superiority of the proposed method in online handwritten music symbol recognition.     

Internet of things system technologies based on quality of experience

Peer-to-Peer Networking and Applications - With rapid development of IOT technology, QOE is considered in design process to ensure that end users are satisfied using IOT applications and System....     

Simple pixel circuits for high resolution and high image quality organic light emitting diode‐on‐silicon microdisplays with wide data voltage range

Two simple pixel circuits are proposed for high resolution and high image quality organic light‐emitting diode‐on‐silicon microdisplays. The proposed pixel circuits achieve high resolution due to simple pixel structure comprising three n‐type MOSFETs and one storage capacitor, which are integrated into a unit subpixel area of 3 × 9 µm² using a 90 nm CMOS process. The proposed pixel circuits improve image quality by compensating for the threshold voltage variation of the driving transistors and extending the data voltage range. To verify the performance of the proposed pixel circuits, the emission currents of 24 pixel circuits are measured. The measured emission current deviation error of the proposed pixel circuits A and B ranges from ?2.59% to +2.78%, and from ?1.86% to +1.84%, respectively, which are improved from the emission current deviation error of the conventional current‐source type pixel circuit when the threshold voltage variation is not compensated for, which ranges from ?14.87% to +14.67%. In addition, the data voltage ranges of the proposed pixel circuits A and B are 1.193 V and 1.792 V, respectively, which are 2.38 and 3.57 times wider than the data voltage range of the conventional current‐source type pixel circuit of 0.501 V.     

Neural Network Based Terrain Classification Using Wavelet Features

Terrain perception technology using passive sensors plays a key role in enhancing autonomous mobility for military unmanned ground vehicles in off-road environments. In this paper, an effective method for classifying terrain cover based on color and texture features of an image is presented. Discrete wavelet transform coefficients are used to extract those features. Furthermore, spatial coordinates, where a terrain class is located in the image, are also adopted as additional features. Considering real-time applications, we applied a neural network as classifier and it is trained using real off-road terrain images. Through comparison of the classification performance according to applied feature sets and color space changes, we can find that the feature vectors with spatial coordinates extracted using the Daub2 wavelet in the HSI color space have the best classification performance. Experiments show that using the wavelet features and spatial coordinates features improves the terrain cover classification performance. The proposed algorithm has a promising results and potential applications for autonomous navigation.     

Design and implementation of Performance Analysis Unit (PAU) for AXI-based multi-core System on Chip (SOC)

With the rapid development of semiconductor technology, more complicated systems have been integrated into single chips. However, system performance is not increased in proportion to the gate-count of the system. This is mainly because the optimized design of the system becomes more difficult as the systems become more complicated. Therefore, it is essential to understand the internal behavior of the system and utilize the system resources effectively in the System on Chip (SOC) design. In this paper, we design a Performance Analysis Unit (PAU) for monitoring the AMBA Advanced eXtensible Interface (AXI) bus as a mechanism to investigate the internal and dynamic behavior of an SOC, especially for internal bus activities. A case study with the PAU for an H.264 decoder application is also presented to show how the PAU is utilized in SOC platform. The PAU has the capability to measure major system performance metrics, such as bus latency, amount of bus traffic, contention between master/slave devices, and bus utilization for specific durations. This paper also presents a distributor and synchronization method to connect multiple PAUs to monitor multiple internal buses of large SOC.