• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.273-284
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• 2020

The performance of Global Navigation Satellite System (GNSS) chipset and Inertial Measurement Unit (IMU) sensors embedded in smartphones for location-based services (LBS) is limited due to the economic reasons for their mass production. Therefore, it is necessary to efficiently process the output data of the smartphone's embedded sensors in order to derive the optimum navigation values and, as a previous step, output performance of smartphone embedded sensors needs to be verified. This paper analyzes the navigation performance of such devices by processing the raw measurements data output from smartphones. For this, up-to-dated versions of smartphones provided by Samsung (Galaxy s10e) and Xiaomi (Mi 8) are used in the test experiment to compare their performances and characteristics. The GNSS and IMU data are extracted and saved by using an open market application software (Geo++ RINEX Logger & Mobile MATLAB), and then analyzed in post-processing manner. For GNSS chipset, data is extracted from static environments and verified the position, Carrier-to-Noise (C/N₀), Radio Frequency Interference (RFI) performance. For IMU sensor, the validity of navigation and various location-based-services is predicted by extracting, storing and analyzing data in static and dynamic environments.

• 경영과학
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• 제13권1호
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• pp.135-156
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• 1996

The purpose of this paper is to study the links between manufacturing strategy and change programs of manufacturing firms in Korea. The nature of our analysis is more descriptive than normative or confirmative. First, we investigate the linkage between manufacturing strategy, manufacturing capability, change programs and performance measurement systems. Secondly, we intend to explore an empirical typology of manufacturing strategy and change programs. The initial findings of the study are as follows: Linkage between manufacturing strategy and change programs of manufacturing firms was not apparent. Flexibility as a strategic priority is positively related to the innovative change programs. There are two distinctive strategies of manufacturing firms in Korea, namely, quality strategy and balanced strategy. We identified three types of change programs, which are incremental change, administrative innovation, and process innovation. Incremental change group has represented low factor score in the change program dimensions. The firms in administrative innovation group mainly depend on information systems and business reengineering. Korean manufacturing firms seem to pursue process improvement by trying simultaneously incremental change in the process, managerial process improvement, and a little bit of innovative change. Performance variable utilization of the firms are not significantly different along with manufacturing strategies and change programs. We found, however, learning and improvement performance dimension is significantly related to flexibility variables. Process innovation group marked high score in usage of learning and improvement indices. The findings of this study seem to have various implications on realigning the manufacturing strategy, change programs, and performance systems in Korean firms.

• 한국기계가공학회지
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• 제20권9호
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• pp.84-89
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• 2021

Indium tin oxide (ITO) transparent electrodes, which are used to manufacture organic light-emitting diodes, are used in light-emitting surface electrodes of display EL panels such as cell phones and TVs, liquid crystal panels, transparent switches, and plane heating elements. ITO is a major component that consists of indium and tin and is advantageous in terms of obtaining sheet resistance and light transmittance in a thin film. However, the optical performance of devices decreases with an increase in its thickness. A digital holography system was constructed and measured for the step measurement of the ITO thin film, and the reliability of the technique was verified by comparing the FE-SEM measurement results. The error rate of the step difference measurement was within ±5%. This result demonstrated that this technique is useful for applications in advanced MEMS and NEMS industrial fields.

• 산업공학
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• 제25권1호
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• pp.71-78
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• 2012

Most manufacturing companies participate in various types of active collaboration to enhance competitive advantages in their arenas. In this paper, we introduce a data warehouse system that is designed for manufacturing collaboration. Just as enterprise information systems, collaboration support systems also need functions of performance measurement and monitoring. For this reason, we devise a new approach to measuring and evaluating performance of manufacturing collaboration. Specifically, we first present a concept of process warehouses for manufacturing collaboration. Next, we design a data schema of collaborative process warehouses to store and monitor collaboration performances. Finally, we implement a prototype system to support performance management of manufacturing collaboration. The proposed system can be used to effectively maintain and continuously improve collaboration in manufacturing industry.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.89-96
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• 2008

This paper investigates the effect of blade deformation, caused by manufacturing inaccuracies, on the performance of a 2-stage axial steam turbine. A high fidelity 3D coordinate Measurement Machine has been employed to obtain the exact geometrical model of the blades. A Streamline Curvature solver was used to predict the overall performance of the turbine. During the manufacturing process of the casts and of the blades themselves, several types of errors can occur which lead to a different geometry from that envisaged by the designer. The main objective of this study is to investigate the effect of those errors on the performance of a 2-stage experimental axial steam turbine. A high fidelity measurement of the actual geometry of both stator and rotor blades has been carried out, using a 3D Coordinate Measurement Machine. The cross sections of the blades obtained by the measurement were compared with those produced by the design process to evaluate the change in blade inlet/exit angles. In addition, the geometrical deviations from the initial design have been subjected to a statistical study in order to locate the nature of the error. The actual(measured) model has been used as input into a Streamline Curvature solver to evaluate its performance. Finally, a comparison with the performance plots of the original geometry has been carried out. A measurable change of efficiency as well as in the total power delivered by the turbine was found. This suggests that the accumulated error caused during the manufacturing procedure plays a significant role in the overall performance of the machine by making it less efficient by more than 1%. Reverse engineering techniques are proposed to predict and alleviate these errors leading thereby to a final design of each stage with improved performance.

• 한국기계가공학회지
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• 제16권3호
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• pp.69-75
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• 2017

There are two types of expensive measuring instruments currently on the market shape measurement and roundness measurement instruments. As they are very expensive, from tens of millions to more than 200 million won, buying them is economically burdensome for small companies or individuals. Therefore, in order to integrate the shape and roundness measurements into a single transfer device, this study aimed to reduce the trial and error by 3D modeling and simulation, and we confirmed the feasibility of operation. Based on these outcomes, a prototype hybrid measuring instrument was fabricated. As a result of performance evaluation and comparative evaluation, we verified the feasibility of implementation and application of the hybrid measuring instrument.

• 한국정보시스템학회지:정보시스템연구
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• 제23권4호
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• pp.75-91
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• 2014

The effective supply chain management(SCM) is a matter of survival in many firms because successful supply chains will effectively coordinate their processes, focus on delivering customer value, eliminate unnecessary costs in key functional areas, and create performance measurement systems. The balanced scorecard(BSC) is widely used to measure the performance of the SCM. The BSC framework suggests that balance is obtained by adopting performance measures from four different areas. In this study, we analyzed the causal relationship of SCM performance based on BSC framework. First, we reviewed the nested causal relationships among four different perspective of the BSC, namely, business process perspective, customer perspective, financial perspective, and innovation and learning perspective. Then, we used the chi-square difference test to identify the best model to fit the causal relationship of SCM performance. Of the 800 questionnaires posted, a total of 265 questionnaires were returned after one follow-up. A total of 66 questionnaires were eliminated due to largely missing values. The major finding says alternative model 3 is dominant to other models to fit causal relationships among four different perspective of the BSC. Innovation and learning perspective positively influence on customer perspective, business process perspective, and financial perspective. Business process perspective also positively influence on customer perspective and financial perspective whereas customer perspective does not influence on financial perspective significantly.

• 한국기계가공학회지
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• 제15권1호
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• pp.103-109
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• 2016

The performance of a multi-head, computerized combination scaling system to automatically identify a group of agricultural products having a total weight within the target range has been optimized to reduce the package cycle time of the merchandise. First, the structure of the scale was modified to enable faster measurement by enhancing the dynamic stability during the process. Second, the high frequency noise in the measured signal was eliminated by a high frequency filter to provide more accurate weight data. Finally, the algorithm to identify a group of products with a total weight within the target range was modified to enable a user to select an optimal number of scales. According to the experimental verifications, this modified system reduced the package cycle time significantly and also was accurate in measuring the total weight of the selected products.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.322-326
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• 1989

This paper describes design procedure of suboptimal control to minimize a performance index which is represented as sum of square output error and the heat input power in arc welding process. Heat input and temperature of a fixed point on the surface of the material are concerned as input and output of the process, repectively. The suboptimal control law considered here in is a proportional plus integral type and is implemented by using only the output variables available from sensor which is also optimally located in a fixed point w.r.t. a moving weld touch.

• KIEAE Journal
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• 제17권4호
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• pp.41-48
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• 2017

Purpose : Currently, 25% of the domestic energy consumption structure is used as building energy, and more than 18% of this energy is consumed in the residential. Accordingly, various efforts and policies that can save energy of the building is being performed. The various researchers are conducting research to diagnose the thermal performance of existing buildings. This study is to apply in the field of precision thermal insulation performance diagnostic method for thermal performance analysis of existing detached house in Seoul, Gangreung, Gyeongju, Pohang. And this paper is analyzed quantitatively measure the existing detached house energy performance. Method: Research methodology analyzed the thermal performance over the Heat Flow Meter method by applying the measurement process and method by applying the criteria of ISO 9869-1 & ASTR method. In this study, the surface heat transfer coefficient was calibrated by applying indoor surface heat transfer resistance with reference to ISO 6946 standard. The measurement error rate between the HFM diagnosis method and the ASTR diagnosis method was reduced and the measurement reliability was obtained through measurement method error verification. Result : As a result of the study, the thermal performance vulnerable parts of the building were quantitatively analyzed, and presented for methods which can be improved capable of efficient energy use buildings.