Interference-free tool path generation in five-axis machining of a marine propeller

The manufacture of a marine propeller typically requires long lead-time to generate five-axis tool paths. It usually takes several days to generate satisfactory tool paths with a general purpose CAD/CAM system. This paper proposes a novel methodology that generates effective five-axis tool paths for marine propellers. The machining of a propeller is accomplished in three steps: rough cut, semi-finish cut, and finish cut. For generating accurate finish cut tool paths, the proposed system computes check vectors that determine a maximum range of valid tool motion based upon tool size and passage width for each CL (Cutter Location) point along the tool path. Interference-free tool paths can be acquired by positioning the tool inside the two check vectors. The modelling capability for propellers is also of importance because it determines the eventual success or failure of the whole process. An iterative B-spline surface modelling technique is employed to improve the accuracy of the models and to increase the productivity. The proposed system generates interference-free tool paths with superior surface finish and reduces lead-time to manufacture a propeller. The system validation and sample results are given and discussed.     

Evaluation and management of new service concepts: An ANP-based portfolio approach

One of the most crucial decisions in service development is concept selection. Nevertheless, little attention has been paid to evaluation of new service concepts (NSCs). This study proposes an analytic network process (ANP) approach to evaluation of NSCs. ANP is a multiple criteria decision making (MCDM) method that can accommodate interdependency among decision attributes. The proposed approach measures feasibility of NSCs in terms of strategy, technology, market, implementation, and operation. The derived feasibility values of NSC alternatives are then employed to construct the NSC portfolio matrix, together with customers’ preference. The NSC portfolio matrix is expected to aid decision making on concept selection and provide managerial implications for service development. A case of the mobile information and entertainment service is presented to illustrate the proposed approach.     

Identification of technological knowledge intermediaries

Intermediaries in a technological knowledge network have recently been highlighted as crucial innovation drivers that accelerate technological knowledge flows. Although the patent network analysis has been frequently used to monitor technological knowledge structures, it has examined only sources or recipients of the technological knowledge by mainly estimating technological knowledge inflows or outflows of a network node. This study, therefore, aims to identify technological knowledge intermediaries when a technology-level knowledge network is composed of several industries. First, types of technological knowledge flows are deductively classified into four types by highlighting industry affiliations of source technologies and recipient technologies. Second, a directed technological knowledge network is generated at the technology class level, using patent co-classification analysis. Third, for each class, mediating scores are measured according to the four types. The empirical analysis illustrates the Korea’s technological knowledge network between 2000 and 2008. As a result, the four types of mediating scores are compared between industries, and industry-wise technological knowledge intermediaries are identified. The proposed approach is practical to explore converging processes in technology development where technology classes act as technological knowledge intermediaries among diverse industries.     

Identifying dynamic knowledge flow patterns of business method patents with a hidden Markov model

As an alternative to the conventional R&D innovation, business models are becoming an important locus of lucrative innovation. Due to the rise of the internet economy, business model innovation today often involves technological innovation, and this can be evidenced by business method (BM) patents. Of several mechanisms that stimulate business model innovation, the role of BM patents is probably most noteworthy. To understand how BM patents play their roles in business model innovation, we need to observe the long-term knowledge flow process. Therefore, we aim to identify dynamic patterns of knowledge flows driven by BM patents using a hidden Markov model (HMM) and patent citation data as an input. An HMM is a popular statistical tool for modelling a wide range of time series data. Since it does not have any general theoretical limit in regard to statistical pattern classification, an HMM is capable of characterizing various temporal patterns. A case study is conducted with the BM patents in 16 USPTO subclasses related to secure transactions. After patterns of the individual subclasses are generated, they are grouped into four major patterns through clustering analysis and their characteristics are closely examined. Our analysis reveals that the BM patents for secure transaction in general play increasingly important roles in advancement of business models, facilitating the transfer of knowledge, and thus can provide valuable insights in formulating more effective strategies or policies for business model innovation.     

Performance Enhancement of Hybrid TDOA/AOA Using Multipath Delay Estimation

Wireless Personal Communications - Wireless solar blind ultraviolet (UV) scattering communication is a new type of atmosphere optics communication technology with the important and potential...     

Identifying and structuring service functions of mobile applications in Google’s Android Market

Recently, mobile applications are considered one of the most opportune issues in mobile industry since the explosive growth of mobile applications has generated the myriad of service functions. In response, it is needed to extract useful information on dominant service functions and structural relationship among the service functions. However, there have been few methods for encapsulating information on major service functions and their relationships. Thus, this study aims at identifying dominant service functions and their structural relationships of mobile applications in Google’s Android Market using frequent pattern (FP)-tree algorithm which retrieves and summarizes frequently used items according to association rules. In this study, the FP-tree algorithm is used for extracting information on service functions in terms of three factors: frequency, association, and hierarchical structure. Using the information of service function tree, the developers refer the systematic and mash-up combinations of service functions to design new mobile applications.     

Effect of Different Quantum Well Structures on the Output Power Performance of GaN-Based Light-Emitting Diodes

We investigated the effect of two different quantum well (QW) structures having different indium contents on the optical performance of fully packaged GaN-based light-emitting diodes (LEDs). Dual-spectrum QW LEDs exhibit ～4% higher external quantum efficiency (at 350 mA) than single-spectrum QW LEDs. However, the two types of LEDs exhibit similar efficiency droop behavior. For both types of LEDs, the output power decreases with increasing junction temperature. When the junction temperature exceeds 70°C, the dual-spectrum QW LEDs exhibit lower output power than the single-spectrum QW LEDs. The wavelength dependence of the output power (at 350 mA) of single-spectrum QW LEDs shows that the LEDs with shorter wavelengths experience more rapid optical degradation than the LEDs with longer wavelengths. Based on the wavelength- and junction-temperature-dependent output power, the droop behavior of the dual-spectrum QW LEDs is described and discussed.     

A 0.003-mm2, 0.35-V, 82-pJ/conversion ultra-low power CMOS all digital temperature sensor for on-die thermal management

In this paper, a 0.35 V, 82 pJ/conversion ring oscillator based ultra-low power CMOS all digital temperature sensor is presented for on-die thermal management. We utilize subthreshold circuit operation to reduce power and adopt an all-digital architecture, consisting of only standard digital gates. Additionally, a linearization technique is proposed to correct the nonlinear characteristics of subthreshold MOSFETs. A bulk-driven 1-bit gated digitally controlled oscillator is designed for the temperature sensing node. Also, a 1-bit time-to-digital converter is employed in order to double the fine effective resolution of the sensor. The proposed digital temperature sensor has been designed in a 90-nm regular V _T CMOS process. After a two-point calibration, the sensor has a maximum error of ?0.68 to +0.61 °C over the operating temperature range from 0 to 100 °C, while the effective resolution reaches 0.069 °C/LSB. Under a supply voltage of 0.35 V, the power dissipation is only 820 nW with the conversion rate of 10K samples/s at room temperature. Also, the sensor occupies a small area of 0.003 mm².     

On the benchmarking method of patent-based knowledge flow structure: Comparison of Korea and Taiwan with USA

Summary This paper suggests an international benchmarking method of disembodied knowledge flow structure. Using patent citation as a proxy measure of disembodied knowledge flow, national knowledge network is developed. Structural equivalence measure is applied to comparing the knowledge network of Korea and Taiwan with that of USA. Static and dynamic comparison make it possible to benchmark disembodied knowledge flow structure efficiently and identify convergent and divergent industries between developing countries and USA. It is also a meso-study that could be conducive to building a comprehensive analytical framework of national innovation system.     

Development of a service evolution map for service design through application of text mining to service documents

As digital convergence has proliferated and products have become smarter, various service concepts have emerged based on the capabilities of products. It has become a main concern to illuminate historical changes and status of service concepts according to the utilisation of product elements to provide valuable information for service development. However, a lacuna still remains in the literature regarding a systematic and quantitative approach on this problem. This study proposes a service evolution map as a tool for analysing the evolutionary paths of service concepts based on the utilisation of product elements. The proposed service evolution map consists of two layers with the time dimension: a product element layer for the utilisation of product elements and a service concept layer for the evolutionary paths of service concepts. Based on the service documents describing what the services are, text mining, co-word analysis, and modified formal concept analysis are employed to develop the product element and service concept layers, respectively. A case study of mobile application services is presented to illustrate the proposed approach. This study is expected to be a basis of future research on the interaction between products and services and service concept design based on the creative utilisation of product elements.