• The Journal of Korea Robotics Society
• /
• v.13 no.1
• /
• pp.55-62
• /
• 2018

In this paper, a method for estimation of external force on an end-effector using joint torque sensor is proposed. The method is based on portion of measure torque caused by external force. Due to noise in the torque measurement data from the torque sensor, a recursive least-square estimation algorithm is used to ensure a smoother estimation of the external force data. However it is inevitable to create a delay for the sensor to detect the external force. In order to reduce the delay, modified recursive least-square is proposed. The performance of the proposed estimation method is evaluated in an experiment on a developed six-degree-of-freedom robot. By using NI DAQ device and Labview, the robot control, data acquisition and The experimental results output are processed in real time. By using proposed modified RLS, the delay to estimate the external force with the RLS is reduced by 54.9%. As an experimental result, the difference of the actual external force and the estimated external force is 4.11% with an included angle of $5.04^{\circ}$ while in dynamic state. This result shows that this method allows joint torque sensors to be used instead of commonly used external sensory system such as F/T sensors.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.1
• /
• pp.51-56
• /
• 2008

The counter-fire operation system performs its mission exchanging information with other related systems such as command & control systems and military information systems. In the process of exchanging information, the counter-fire operation system uses a type of data message which contains exchange data information in the format of KMTF. The requirement of data exchange of count-fire operation will continue to evolve. But the EDX(External Data eXchange) configuration item of the current counter-fire operation system can not effectively cope with the variation of data exchange requirements due to its fixed software structure. In the paper, a solution for improving flexibility of external data exchange in counter-fire operation system is proposed.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.23 no.5
• /
• pp.379-384
• /
• 2013

For effective ship management in VTS(Vessel Traffic Service), it needs to assess the external force acting on ship. Big data in maritime traffic can be roughly categorized into two groups. One is the traffic information including ship's particulars. The other is the external force information e.g., wind, sea wave, tidal current. This paper proposes the method to assess the external force acting on ship using big data in maritime traffic. To approach Big data in maritime traffic, we propose the Waterway External Force Code(WEF code) which consist of wind, wave, tidal and current information, Speed Over the Water(SOW) of each ship, weather information. As a results, the external force acting a navigating ship is estimated.

• Information and Communications Magazine
• /
• v.30 no.10
• /
• pp.79-85
• /
• 2013

By interacting with external wireless sensors, smartphones can gather high-fidelity data on the surrounding environment to develop various environment-aware, personalized applications. In this work we introduce the sensor virtualization module (SVM), which virtualizes external sensors so that smartphone applications can easily utilize a large number of external sensing resources. Implemented on the Android platform, our SVM simplifies the management of external sensors by abstracting them as virtual sensors to provide the capability of resolving conflicting data requests from multiple applications and also allowing sensor data fusion for data from different sensors to create new customized sensors elements. We envision our SVM to open the possibilities of designing novel personalized smartphone applications.

• Steel and Composite Structures
• /
• v.8 no.2
• /
• pp.99-114
• /
• 2008

This paper presents the theoretical simulation of the response of 1020 carbon steel tubes subjected to symmetric and unsymmetric cyclic bending with or without external pressure by using the endochronic theory. Experimental data of 1020 carbon steel tubes tested by Corona and Kyriakides (1991) were used for evaluating the theoretical simulation. Several cases were considered in this study, they were symmetric bending without external pressure, symmetric bending with external pressure, unsymmetric bending without external pressure, and unsymmetric bending with external pressure. The responses of the moment-curvature, ovalization-curvature and ovalization-number of cycles with or without external pressure were discussed. It has been shown that the theoretical simulations of the responses correlate well with the experimental data.

• Journal of the Korean Data and Information Science Society
• /
• v.14 no.2
• /
• pp.265-274
• /
• 2003

Time series data are influenced by the external events such as holiday, strike, oil shock, and political change, so the external events cause a sudden change to the time series data. We regard the observation as outlier that occurred as a result of external events. In general, it is called intervention if we know the period and the reason of external events, and it makes an analyst difficult to establish a time series model. Therefore, it is important that we analyze the styles and effects of intervention. In this paper, we considered the linear time series model with invention and compared with nonlinear time series models such as ARCH, GARCH model and also we compared with the combination prediction method that Tong(1990) introduced. In the practical case study, we compared prediction power with RMSE among linear, nonlinear time series model with intervention and combination prediction method.

• Journal of Preventive Medicine and Public Health
• /
• v.35 no.3
• /
• pp.236-244
• /
• 2002

Objective : To empirically investigate the relationship of internal and external customer satisfactions, service quality, and customer loyalty in medical services. Methods : This essay proposes an integrated model to explain the causality of internal and external customer satisfactions, service quality, and customer loyalty. To this end, a structural model was developed, consisting of the following factors: internal and external customer satisfactions, service quality, and customer loyalty. The study included 214 sets of data, with 107 sets being collected for both out-patients and in-patients. The data were analyzed using AMOS 4.0. Results : We found the greater the internal customer satisfaction, the greater the out-patient quality of service quality. Secondly, the greater the service quality, the greater the external customer satisfaction of both in- and out-patients. The service quality of doctors, compared to that of the nurses, had a greater effect on external customer satisfaction. Thirdly, the service quality of doctors and nurses affected both internal and external customer satisfactions, which ultimately affected the customer loyalty. Finally the greater the external customer satisfaction, the greater the customer loyalty. Conclusion : This Study confirms the positive relationship among the internal and external customer satisfactions, service quality, and customer loyalty, which proves the doctors quality of service is the primary factor for external satisfaction, and customer loyalty relating to medical services.

• Asia-Pacific Journal of Business
• /
• v.14 no.1
• /
• pp.215-229
• /
• 2023

Purpose - Based on the funding-horizon theory, this study aims to test the effects of cash needs and the persistence of external funding needs on firms' external financing. Design/methodology/approach - Financial data of Korean listed companies were collected from DataGuide. Immediate and near-term cash shortfalls are defined using the methodology of Haung and Ritter (2021). We estimate multinomial logit regressions for the financing choice. Findings - First, all three cash depletion variables used in our study increase the likelihood of external financing. Second, firms prefer to issue debt to meet immediate spending and equity to meet long-lived cash needs. Third, this effect is more pronounced for high R&D firms. Fourth, chaebol firms with internal capital markets defer raising external capital for immediate and near-term cash needs. Research implications or Originality - This paper provide empirical evidence that immediate and near-term cash needs induce external financing, and the persistence of cash needs affects the choice between debt and equity, the finding which is consistent with the funding-horizon theory of financing decisions. Being the first paper to test the funding-horizon theory using Korean data, this paper contributes to the literature on the capital structure of Korean firms.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.4
• /
• pp.125-136
• /
• 2016

The external R&D, which includes the adoption of the external technology and knowledge in addition to the internal R&D, is one of important factors for the innovation. Especially for small and medium-sized enterprises (SMEs), the external R&D has been considered as a key factor to carry out the innovation more efficiently due to the limitations of their resources and capacities. However, most of extant studies related to external R&D have focused on analyzing the influence of external R&D on innovation outputs or outcomes. Only a few studies have explored the impact of external R&D on the innovation efficiency. This study therefore investigates whether the external R&D effects the industry's innovation efficiency and productivity. On this study, we used Korean manufacturing industry data of SMEs from 2012 to 2014 and employed a global Malmquist productivity analysis technique, which is based on the Data Envelopment Analysis (DEA), to assess the innovation efficiency and productivity. Innovation performances of external R&D group and internal R&D group are compared. Then, the sectoral patterns of both innovation efficiency and productivity are analyzed with respect to the technological intensity, which is introduced by OECD. The results show that the gap of innovation efficiency between external and internal R&D groups has gradually decreased because of the continuous improvement of the external R&D group's performance, while the external R&D group lag behind the internal R&D group. In addition, patterns of the innovation efficiency and productivity change were different depending on the technological intensity, which means that the higher the technological intensity, the greater the effect of external R&D.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.41 no.3
• /
• pp.129-137
• /
• 2018

VOCs have been used as the most definitive resource to reflect customer feedback when developing products and services. However, due to the development of the Internet and the emergence of SNS, VOC is no longer the only channel that represents customer opinions. There are also a number of studies showing that many customers express complaints through channels other than VOCs. In this paper, we analyze the difference between the official VOC data and the data collected through the external channel, and suggest ways to reflect the various opinions of customers. To do this, this study uses keyword analysis that can identify differences according to frequency through social network, modular analysis to distinguish topics according to centrality and similarity, and emotional analysis to confirm word polarity (positive and negative). The results of this study show that the opinions of the customers were different depending on channels such as VOCs and external channels. Therefore, the collected data through VOC as well as external channels should be used in order to reflect the opinions of customers. In particular, this paper confirms that the results of one channel may vary depending on the channel characteristics even for the same channel. This confirms that collecting voc only on certain channels may differ from what real customers require. Therefore, data collected through VOCs as well as external channels must be used to reflect various customer feedback.