Disparate attributes algorithm for semantic assembly design rule management

To expedite a semantic product design environment, the relevant minimal set of design rules could optimally be distilled from the given disparate design rules. However, in disparate design rules, some attributes are frequently unused in other design rules. Treating all the attributes in all the rules increases reasoning complexity. In the situation of incomplete information, treating the attributes, which may be relevant to some rules and not to others, as “missing” ones is found to cause reasoning problems. In this paper, we present a new algorithm, i.e. the disparate attributes algorithm, for managing semantic assembly design rules. The proposed disparate attributes algorithm by identifying “inapplicable” information extends a rough set approach for managing semantic assembly design rules with systematic selection of various minimal sets of rules. To validate the disparate attributes algorithm, the approach is tested with multiple realistic assembly design cases.     

Cognitive evaluation for conceptual design: cognitive role of a 3D sculpture tool in the design thinking process

ABSTRACT

This study focuses on the decisive role played by the digital design environment in the cognitive design process and design thinking. To analyse the cognitive role of digital design tools, we carried out a protocol analysis of conventional design sketching and a 3D sculpture tool. Cognitive evaluation was a differentiating factor when considering the contextual role of the 3D sculpture tool in subsequent evaluations, non-sequential evaluations for conversion, and passive approaches within the design process. Cognitive evaluation played the following roles: validation, extension, navigation, exploration, and confirmation. The navigation, exploration, and extension roles played by non-sequential evaluation were mainly related to inductive design thinking. Finally, the types of cognitive evaluation and their roles when using the 3D sculpture tool were different, according to the design thinking type. This study explored the multidimensional roles of cognitive evaluation using a 3D sculpture tool and its relationship with design thinking types.     

Degradation of organic dye using zero-valent iron prepared from by-product of pickling line

In this study, zero-valent iron (ZVI) was produced using iron oxide that is a by-product of a pickling line at a steel works. The reaction activity of the produced ZVI was evaluated through a series of decomposition experiments of Orange II aqueous solution. The size of ZVI particles increased with reduction temperature due to coalescence. Correspondingly, the specific surface area of ZVI decreased with increasing reduction temperature. The decomposition efficiency of synthesized ZVI particles was higher at a lower pH. In particular, no significant decomposition reaction was observed at pH of 4 and higher. The rate of the ZVI-assisted decomposition of Orange II was increased by addition of H2O2 at pH of 3, whereas it was reduced by addition of H2O2 at a higher pH of 6. Nevertheless, simultaneous use of ZVI, UV and H2O2 led to a considerable increase in the decomposition rate even at a high pH condition (pH = 6).     

Presence, molecular characteristics and geosmin producing ability of actinomycetes isolated from South Korean terrestrial and aquatic environments

The unpleasant odor of drinking water is one of the major problems in many water utilities in the world. Actinomycetes have long been associated with odorous compounds. Considering the paucity of research on Actinomycetes producing odorous compounds in South Korea, presence of Actinomycetes, their molecular characteristics and ability to produce odorous compounds were investigated in this study. Findings confirmed the presence of Actinomycetes in surface soil, sediment, and water samples from four sites: two artificial lakes [Paldang and Cheongpyeong (CP)], and two streams [Gyeongan (GA) and Yangpyeong]. Surface soil and sediment from CP area had the greatest concentration of Actinomycetes (8.2 x 10(7) and 6.8 x 10(6) colony forming units (CFUs)/gram, dry weight, respectively). When water samples are considered, samples from GA had the highest concentration (1.9 x 10(2) CFU/mL). 16S rRNA sequencing and molecular phylogenetic analysis showed that Streptomyces was the dominant genus (64.1%). In addition, the isolated Actinomycetes synthesized 5.4 ng/L geosmin as demonstrated by thermal desorption unit-gas chromatograph/mass spectrometry analysis.     

Biodegradation of estrogen conjugates by bacteria isolated from river sediments

The objective of this study was to investigate the ability of E. coli in river sediments to degrade estrogen conjugates. Biodegradation experiments on glucuronide estrogens (E1-GLU, E2-GLU and E3-GLU) using E. coli, non-E. coli bacteria as well as sediment crude extracts were carried out in batch mode. A pure identified E. coli strain (KCTC 2571) was used for comparison of enzyme activity. The results showed that the degradation rate of estrogen conjugates by KCTC 2571 and E. coli isolated from sediments followed a similar trend. Fecal bacteria showed a high ability to deconjugate glucuronided estrogens. Approximately 50% of glucuronide moieties were cleaved within 4 h of contact time in experiments using pure E. coli. The degradation rate was slower in experiments using crude extracts of sediments, and conjugated estrogens were not completely degraded even after 12 h of reaction. These results provide a clear understanding of the fate and behavior of estrogen by bacteria in the environment.     

A Lyapunov functional approach to robust stability analysis of continuous-time uncertain linear systems in polytopic domains

In this paper, a sufficient linear matrix inequality (LMI) condition is presented for robust stability analysis of continuous-time linear time-invariant (LTI) systems in polytopic domains. The underlying idea behind the proposed approach is to introduce a family of complex functions which map the closed right-hand side of the complex plane into the inside of the closed unit circle centered at the origin. Then, the mapping properties are used to assure that all the eigenvalues of a system are located in the open left-hand side of the complex plane. Examples show the validity of the proposed condition.     

A finite memory filtering for end-to-end available bandwidth estimation

In this paper, a finite memory filter is proposed to estimate the available bandwidth through real-time tracking unknown parameters of the sloping straight line while removing undesired system and measurement noises. The finite memory filter is developed under a weighted least square criterion using only the most recent finite probe-packet measurements on the window. The proposed finite memory filtering based available bandwidth estimate is shown to have several inherent properties such as unbiasedness, deadbeat, and robustness. A guideline for choosing appropriate window length is described as it can significantly affect the estimation performance. Finally, computer simulations show that the proposed finite memory filtering based approach can be comparable with the Kalman filtering based approach with infinite memory structure for constantly or slowly changing available bandwidth and outperform that for dynamically changing available bandwidth.     

Forward kinematic singularity avoiding design of a Schönflies motion generator by asymmetric attachment of subchains

In most of the previous studies on parallel mechanisms (PMs), architectural design mainly relying on symmetric geometry was investigated without in-depth analysis of its performance. This work demonstrates that such a symmetric geometry of multiple subchains sometimes induces a forward kinematic singularity which degrades the overall kinematic performance of PMs within the desired workspace and claims that an asymmetric attachment of those subchains on a moving platform can effectively resolve such a singularity problem. A 4-Degree-of-Freedom (DOF) PM exhibiting Schönflies motions is examined as an example device. First, its mobility analysis and kinematic modeling via screw theory are conducted. Then a singularity analysis based on Grassmann line geometric conditions is carried out, and the forward kinematic singularities of the mechanism are identified and verified by simulations. Based on these analysis and simulations, a forward kinematic singularity-free design is suggested. To show the high potential of the device in practical applications, its output stiffness and dynamic motion capability are examined. Then a prototype is built and its motions capability is verified through experiments.     

Discipline-based instruction to promote interdisciplinary design of wearable and pervasive computing products

This paper reports on a design experience for undergraduates in computer engineering, industrial design, and marketing that focuses on pervasive computing devices. Across a broad range of targeted application areas and user groups, many of the student designs have been wearable computers. Consequently, our course will be of interest to the wearable computing community, particularly in terms of our aim of bridging the gap between design and engineering. For the two most recent offerings of the course, we have utilized external observers and surveyed the students in order to validate the impact of aspects of our process and changes to it. This paper is based upon 5 years of experience and 2 years of analysis of our course, and it presents an overview of our process with both qualitative and quantitative results from these two most recent offerings.     

Compact and unified hardware architecture for SHA-1 and SHA-256 of trusted mobile computing

This paper presents a compact and unified hardware architecture implementing SHA-1 and SHA-256 algorithms that is suitable for the mobile trusted module (MTM), which should satisfy small area and low-power condition. The built-in hardware hash engine in a MTM is one of the most important circuit blocks and dominates the performance of the whole platform because it is used as a key primitive to support most MTM commands concerning to the platform integrity and the command authentication. Unlike the general trusted platform module (TPM) for PCs, the MTM, that is to be employed in mobile devices, has very stringent limitations with respect to available power, circuit area, and so on. Therefore, MTM needs the spatially optimized architecture and design method for the construction of a compact SHA hardware. The proposed hardware for unified SHA-1 and SHA-256 component can compute a sequence of 512-bit data blocks and has been implemented into 12,400 gates of 0.25 μm CMOS process. Furthermore, in the processing speed and power consumption, it shows the better performance in comparison with commercial TPM chips and software-only implementation. The highest operation frequency and throughput of the proposed architecture are 137 MHz and 197.6 Mbps, respectively, which satisfy the processing requirement for the mobile application.