• Bulletin of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.365-370
• /
• 2014

For real-time monitoring of colloidal nanoparticles (NPs) in aqueous media, a light sheet type dark-field microscopy system combined with a microfluidic concentration gradient generator (${\mu}FCGG$-LSDFM) was developed. Various concentrations of colloidal Au NPs were simultaneously generated with the iFCGG and characterized with the LSDFM setup. The number concentrations and hydrodynamic size distributions were measured via particle counting and tracking analysis (PCA and PTA, respectively) approaches. For the 30 nm Au NPs used in this study, the lower detection limit of the LSDFM setup was 3.6 ng/mL, which is about 400 times better than that of optical density measurements under the same ${\mu}FCGG$ system. Additionally, the hydrodynamic diameter distribution of Au NPs was estimated as $39.7{\pm}12.2nm$ with the PTA approach, which agrees well with DLS measurement as well as the manufacturer's specification. We propose this ${\mu}FCGG$-LSDFM setup with features of automatic generation of NP concentration gradient and real-time monitoring of their physicochemical characteristics (e.g., number concentration, and hydrodynamic size distribution) as an important component of future high-throughput screening or high-content analysis platforms of nanotoxicity.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.3
• /
• pp.339-348
• /
• 2011

Reconfigurable manufacturing system (RMS), alternatively called changeable manufacturing, is a new manufacturing paradigm designed for rapid change in hardware and software components in order to quickly adjust production capacity and functionality in response to sudden changes in market or in regulatory requirements. Although there has been much progress in hardware components during the last decade, not much work has been done on operational issues of RMS. As one of starting studies on the operational issues, we suggest a framework for the system setup and scheduling problems to cope with the reconfigurability of RMS. System setup, which includes batching, part grouping, and loading, are concerned with the pre-arrangement of parts and tools before the system begins to process, and scheduling is the problem of allocating manufacturing resources over time to perform the operations specified by system setup. The framework consists of 8 scenarios classified by three major factors: order arrival process, part selection process, and tool magazine capacity. Each of the scenarios is explained with its subproblems and their interrelationships.

• Proceedings of the Korea Contents Association Conference
• /
• 2004.11a
• /
• pp.220-227
• /
• 2004

In this paper, we made out blocking probability analysis for a new authentication structure for reducing the certificate acquisition time which is one of the factors that should be improved in a conventional wireless PKI. A conventional key exchange method simply performs the key exchange setup step based on discrete algebraic subjects. But the mutual-authentication procedure of wireless PKI for reducing authentication time uses an elliptical curve for a key exchange setup step. Besides, we proposed advanced handover method and blocking probability analysis for wireless PKI.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.4
• /
• pp.22-28
• /
• 2007

The welded defects are usually called user's unsatisfaction for appearance and functional usage. For checking these defects effectively without time loss, setup of weldability estimation system is an important for detecting whole specimen quality. In this study, after catching a rawdata on welded specimen profiles and treating vision processing with these data, the qualitative defects are estimated from getting these information by laser vision camera at first. At the same time, the weldability estimation for whole specimen is produced. For user friendly, the weldability estimation results are shown each profiles, final reports and visual graphics method. So, user can easily determined weldability. By applying these system to welding fabrication, these technologies are contribution to on-line setup of weldability estimation system.

• Journal of the military operations research society of Korea
• /
• v.27 no.2
• /
• pp.25-36
• /
• 2001

In this paper a new heuristic algorithm has been developed and presented for logistics for multiple objectives in an automated manufacturing systems. We proposed Simallest Processing and Average setup time Ratio First(SPARF) algorithm for multiple criteria under sequence setup time. The heuristic algorithm is implemented on the various problem cases by number of jobs and machines. The proposed algorithm provided smaller than the previously documented heuristics. The results obtained show a superior solution by the new heuristic over previous heuristics on all problem sizes. we perform analyses of variance to fortify the above results of comparison with the previous algorithms to the four cases using Statistical Analysis System(SAS) package. The results show that the larger is the number of groups or cells, the bigger is the amount of improvement by the proposed algorithms. It suggests that the algorithms proposed is strongly influenced by the number of cells, groups and interaction of these factors.

• Journal of the Korea Safety Management & Science
• /
• v.25 no.2
• /
• pp.1-8
• /
• 2023

This paper is proposing a novel machine scheduling model for the unrelated parallel machine scheduling problem without setup times to minimize the total completion time, also known as "makespan". This problem is a NP-complete problem, and to date, most approaches for real-life situations are based on the operator's experience or simple heuristics. The new model based on the Memetic Algorithm, which was proposed by P. Moscato in 1989, is a hybrid algorithm that includes genetic algorithm and local search optimization. The new model is tested on randomly generated datasets, and is compared to optimal solution, and four scheduling models; three rule-based heuristic algorithms, and a genetic algorithm based scheduling model from literature; the test results show that the new model performed better than scheduling models from literature.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.5 no.12
• /
• pp.2355-2373
• /
• 2011

Vision-based vehicle detector systems are becoming increasingly important in ITS applications. Real-time operation, robustness, precision, accurate estimation of traffic parameters, and ease of setup are important features to be considered in developing such systems. Further, accurate vehicle detection is difficult in varied complex traffic environments. These environments include changes in weather as well as challenging traffic conditions, such as shadow effects and jams. To meet real-time requirements, the proposed system first applies a color background to extract moving objects, which are then tracked by considering their relative distances and directions. To achieve robustness and precision, the color background is regularly updated by the proposed algorithm to overcome luminance variations. This paper also proposes a scheme of feedback compensation to resolve background convergence errors, which occur when vehicles temporarily park on the roadside while the background image is being converged. Next, vehicle occlusion is resolved using the proposed prior split approach and through reasoning for rule-based tracking. This approach can automatically detect straight lanes. Following this step, trajectories are applied to derive traffic parameters; finally, to facilitate easy setup, we propose a means to automate the setting of the system parameters. Experimental results show that the system can operate well under various complex traffic conditions in real time.

• Journal of Korean Institute of Industrial Engineers
• /
• v.33 no.3
• /
• pp.373-380
• /
• 2007

In this paper, we consider a new lot-sizing and scheduling problem (LSSP) that minimizes the sum of production cost, setup cost and inventory cost. Setup carry-over and overlapping as well as demand splitting are considered. Also, maximum number of setups for each time period is not limited. For this LSSP, we have formulated a mixed integer programming (MIP) model, of which the size does not increase even if we divide a time period into a number of micro time periods. Also, we have developed an efficient heuristic algorithm by combining decomposition scheme with local search procedure. Test results show that the developed heuristic algorithm finds good quality (in practice, even better) feasible solutions using far less computation time compared with the CPLEX, a competitive MIP solver.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.5
• /
• pp.879-886
• /
• 2006

In this paper, we proposed an advanced authentication structure for reducing the certificate acquisition time which is one of the factors that should be improved in a conventional wireless PKI. A conventional key exchange method simply performs the key exchange setup step based on discrete algebraic subjects. But the mutual-authentication procedure of wireless PKI for reducing authentication time uses an elliptical curve for a key exchange setup step. We simulated and compared the authentication structure proposed by Sufatrio, K. Lam[4] and the our authentication structure in terms of the authentication time. Simulation results show that the proposed method reduces the authentication time comparing to the conventional wireless PKI authentication method.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.11a
• /
• pp.127-133
• /
• 2006

Minimizing the total number of setup changes of a machine increases the throughput and improves the stability of a production process, and as a result enhances the product quality. In this context, we consider a new product-mix problem that minimizes the total number of setup changes while producing the required quantities of a product over a given planning horizon. For this problem, we develop a mixed integer programming model. Also, we develop an efficient heuristic algorithm to find a feasible solution of good quality within reasonable time bounds. Computational results show that the developed heuristic algorithm finds a feasible solution as good as the optimal solution in most test problems. Also, we developed a web based scheduling and monitoring system for a zinc alloy production process using the developed heuristic algorithm. By using this system, we could find a monthly zinc alloy production schedule that significantly reduces the total number of setup changes.