• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.1
• /
• pp.786-791
• /
• 2021

In this paper, in order to minimize limitations such as signal interference and positioning errors in existing indoor positioning systems, a smart LED-based positioning system for excellent line-of-sight radio environments and precise location tracking is proposed to improve accuracy. An IEEE 802.4 Zigbee module is mounted on the SMPS board of a smart LED; RSSI and LQI signals are received from a moving tag, and the system is configured to transmit the measured data to the positioning server through a gateway. For the experiment, the necessary hardware, such as the gateway and the smart LED module, were separately designed, and the experiment was conducted after configuring the system in an external field office. The positioning error was within 70cm as a result of performing complex calculations in the positioning server after transmitting a vector value of the moving object obtained from the direction sensor, together with a signal from the moving object received by the smart LED. The result is a significantly improved positioning error, compared to an existing short-range wireless communications-based system, and shows the level at which commercial products can be implemented.

• Journal of the Institute of Convergence Signal Processing
• /
• v.4 no.2
• /
• pp.61-69
• /
• 2003

In this paper, we developed the U parameter test system which inspects the property of DC parameter for semiconductor products. The developed system is interfaced by IBM-PC. It is consisted of CPLD part, ADC (Analogue to Digital Converter), DAC (Digital to Analogue Converter), voltage/current source, variable resistor and measurement part. In the proposed system, we have designed the constant voltage source and the constant current source in a part. The CPLD part is designed by VHBL, which it generates the control and converts the serial data to parallel data. The proposed system has two test channels and it operates VFCS mode and CFVS mode. The range of test voltage is from 0[V] to 100[V], and the range of test current is from 0[mA] to 100[mA)]. The diode is tested. The test results have a good performance.

• Industrial Engineering and Management Systems
• /
• v.13 no.3
• /
• pp.289-296
• /
• 2014

With society becoming more advanced and complex, the required management engineering makes essential the development of human resources that can propose solutions for problems of new phenomena from a different perspective. As an example of such phenomena, we note a consumer electronics 'Eco-point' system campaign in this study. To mitigate global warming, revitalize the economy, and encourage the adoption of terrestrial digital compatible TVs, the consumer electronics Eco-point system campaign was implemented in May 2009 in Japan. In this study, we note a model which is constant term with exponential curve with notion of the growth phenomenon (Nakagiri and Kurita, Journal of the Operations Research Society of Japan, 2002). In our study, we call this model the 'differential equation model of the growth phenomenon.' This model represents a phenomenon with a hierarchical structure for capturing the properties of n species. In this study, we propose a new model which can represent not only the impact of largescale campaigns but also seasonal factors. Accordingly, we understand the phenomenon of fluctuation of sales of some products caused by large-scale campaigns and predict the fluctuation of sales. The final goal of this study is to develop human resources that can propose provision and solution for pre-consumption and reactionary decline in demand by understanding the impact of large-scale campaigns. As the first step of this goal, our objective is to propose a new regression method with different conventional perspective that can describe the fluctuation of sales caused by large-scale campaigns and show the possibility of new management engineering education.

• Journal of Computational Design and Engineering
• /
• v.3 no.4
• /
• pp.363-369
• /
• 2016

Cyber Physical System (CPS) and Internet of Things (IoT) are hot objects of interest as an extension of the embedded system. These interactive products and systems contain Mobile Devices which are most popular and used most frequently. Also these have been widely used from the control of the Nuclear Power Control System (NPCS) to IoT Home Service. Information & Communication Technology (ICT) topics of trend fused-complex current Information Technology (IT) and Communication Technology (CT) are closely linked to real space and virtual space. This immediately means the arrival of the ultra-connected society. It refers to a society in which various objects surrounding the human innovation and change in the social sector are expected through the connection between the data which are to be generated. In addition, studies of Tool-kit for the design of such systems are also actively pursued. However, only increased cooperation and information sharing between the physical object consists of a variety of machinery and equipment. We have taken into consideration a number of design variables of the high barriers to entry about the product. In this study, It has been developed a Web-based collaboration framework which can be a flexible connection between macroscopically virtual environment and the physical environment. This framework is able to verifiy and manage physical environments. Also it can resolve the bottlenecks encountered during the base expansion and development process of IoT (Internet of Things) environment.

• The Korean Journal of Community Living Science
• /
• v.24 no.2
• /
• pp.251-258
• /
• 2013

Korean oil and honey Yukwa has been paid attention as formal cake for traditional national seasons' holiday and religious service. Quality of Yukwa, however, has been maintained arbitrarily by each Yukwa manufacturer. Since even same Yukwa had severe differences in size, weight, and pattern, it has given the negative effect to the consumer. Yukwa industries need to setup the quantitative quality specifications instead of qualitative ones to maintain the uniformity of Yukwa quality. Efficient and economical inspection and process control system should be developed. In developing quality standards of Yukwa, features which can measure quality quantitatively in real time should be properly chosen. Existing quality features such as acidity, oxidization, hardness, viscosity, and texture were measured by the chemical or physical base destructive methods. Many research and developments have been performed in investigating and analyzing chemical transition states of those quality features as environment or storage condition changes. Most methods, however, require either off-line or complex treatment or time consuming process of analysis in evaluating quality features. Consumer, however, selects products mostly based on the external features such as shape, size, and color. Therefore, critical visual quality features should be chosen and the efficient real time measurement system must be developed. In this paper, computer image acquisition and processing system were developed and software modules were developed to extract the quantitative data of those features in real-time. Computer image processing system will promote in maintaining uniform quality of Yukwa and establishing quality standards of Yukwa.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.3
• /
• pp.252-272
• /
• 2017

Fuel cell systems have to satisfy acceptable operating reliability, sufficient lifetime and price to enter the market in competition with existing products. Fuel cells are made up of complex element technologies and various problems related to the failure of the components can affect the reliability and safety of the system. This problem can be overcome by introducing a monitoring and supervisory control system in addition to automatic control to detect the failure of the fuel cell quickly and properly diagnose the performance degradation. For the fault detection and diagnosis of polymer electrolyte fuel cells, the model based method using the theoretical superposition value and the non-model based method of checking the signal tendency or the converted signal characteristic can be applied. The methods analyzed in this paper can contribute to the development of integrated monitoring and control technology for the whole system as well as the stack.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.8B
• /
• pp.549-561
• /
• 2005

As Internet and network technologies have been developed, e-commerces are getting more complex and more various. This paper, for meta-data and data exchange between heterogeneous database systems, uses XML schema proposed in W3C, and XML schema can present meta-data and data of relational database system as XML document format which is structural. It supports various primitive data formats, so that it uses the structure which reflects adequately data formats which relational database system offered. However, current e-commerces use heterogeneous platforms, so difficulties that is mutual interchange and management exist. For the solution for these problems, a standard ontology which defines relations of product classifications and the standard of property expression and the location ontology which offers e-commerce's information about products are constructed. Applying these ontology information to search system, by offering information which customers need efficient search is performed. Combining these ontologies and product classification category information, called XMDR, this XMDR is introduced into product search system, so this paper proposes to construct ontology server method for efficient search.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.3
• /
• pp.78-86
• /
• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• The KIPS Transactions:PartD
• /
• v.16D no.3
• /
• pp.433-440
• /
• 2009

As information technology of constructional area develops recently, web-based on-line system is rapidly increasing to provide information on diverse constructional materials so as to enhance productivity of constructional business and to reduce cost. Since the constructional materials information provided by these systems, i.e., quality, specification, etc are not standardized, however, the staffs on the constructional site suffer considerable difficulties in using materials information when acquiring information on specific materials, e.g., using diverse information systems or repeating similar jobs. Thus, this research typified information items of constructional materials on the basis of GDAS and designed multi system model to control integrated information on constructional materials. This system can efficiently control and utilize materials information by supporting automatic classification of constructional materials to which OmniClass Part-22 and UNSPSC are applied, conditional complex retrieval of materials information, real-time automatic embodiment of electronic catalog and retrieving/controlling RFID.

• Korean Journal of Chemical Engineering
• /
• v.35 no.12
• /
• pp.2327-2335
• /
• 2018

Fluid catalytic cracking (FCC) is an important chemical process that is widely used to produce valuable petrochemical products by cracking heavier components. However, many difficulties exist in modeling the FCC process due to its complexity. In this study, a dynamic process model of a FCC process is suggested and its structural observability is analyzed. In the process modeling, yield function for the kinetic model of the riser reactor was applied to explain the product distribution. Hydrodynamics, mass balance and energy balance equations of the riser reactor and the regenerator were used to complete the modeling. The process model was tested in steady-state simulation and dynamic simulation, which gives dynamic responses to the change of process variables. The result was compared with the measured data from operating plaint. In the structural analysis, the system was analyzed using the process model and the process design to identify the structural observability of the system. The reactor and regenerator unit in the system were divided into six nodes based on their functions and modeling relationship equations were built based on nodes and edges of the directed graph of the system. Output-set assignment algorithm was demonstrated on the occurrence matrix to find observable nodes and variables. Optimal locations for minimal addition of measurements could be found by completing the whole output-set assignment algorithm of the system. The result of this study can help predict the state more accurately and improve observability of a complex chemical process with minimal cost.