• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.459-464
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• 2023

The mobile house of this article is provided with stand-alone power system that uses photovoltaic energy and enables sensing and environmental monitoring. Excess power generated is stored in lithium batteries, which enable smooth operation of the mobile house even in environment in which solar energy cannot be used. The house has been designed that its systems can be operated continuously by diesel power generation even when photovoltaic energy cannot be generated due to long rainy season or heavy snow. BMS (batter management system) has been constructed for photovoltaic and power management, and monitors the charge/discharge and usage amount of photovoltaic energy. Various sensing data are recorded and transmitted automatically, and the design allows for wireless monitoring by means of computer and smartphone app. The container house proposed in this study enables efficient energy management by performing optimal energy operation in remote areas, parks, event venues, and construction sites where there is no system power source.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1846-1855
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• 2015

In this paper, a precise relative positioning with TD(time differenced) carrier phase measurements from a low-cost GNSS(Global Navigation Satellite System) receiver is proposed and analysed. The proposed method is using carrier phase measurement from a single GNSS receiver that reference receiver is not required and stand alone positioning is possible. TD operation removes the troublesome integer ambiguity resolution problem, and if the time interval is short, other error, such as, ionospheric, tropospheric delay and ephemeris error are effectively eliminated. The error analysis of the proposed method shows that a precise and positioning with carrier phase is possible. The implemented system is evaluated using a real car experiments. The results show that the horizontal positioning error was less than 3m during 10 minutes experiments, which is 4 times more precise than the results of normal code based absolute positioning.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.128-135
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• 2010

This paper introduces step by step procedures for the fabrication and operation of an embedded solar tracker. The system presented consists of application software, compactRIO, C-series interface module, analogue input module, step drive, step motor, feedback devices and other accessories to support its functional stability. CompactRIO that has a real-tim processor allows the solar tracker to be a stand-alone real time system which operates automatically without any external control. An astronomical method and an optical method were used for a high-precision solar tracker. CdS sensors are used to constantly generate feedback signals to the controller, which allow a solar tracker to track the sun even under adverse conditions. The database of solar position and sunrise and sunset time was compared with those of those of the Astronomical Applications Department of the U.S. Naval Observatory. The results presented here clearly demonstrate the high-accuracy of the present system in solar tracking, which are applicable to many existing solar systems.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.293-299
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• 2007

Objective : Thoracoscopic spinal surgery provides minimally invasive approaches for effective vertebral decompression and reconstruction of the thoracic and thoracolumbar spine, while surgery related morbidity can be significantly lowered. This study analyzes clinical results of thoracoscopic spinal surgery performed at our institute. Methods : Twenty consecutive patients underwent video-assisted thoracosopic surgery (VATS) to treat various thoracic and thoracolumbar pathologies from April 2000 to July 2006. The lesions consisted of spinal trauma (13 cases), thoracic disc herniation (4 cases), tuberculous spondylitis (1 case), post-operative thoracolumbar kyphosis (1 case) and thoracic tumor (1 case). The level of operation included upper thoracic lesions (3 cases), midthoracic lesions (6 cases) and thoracolumbar lesions (11 cases). We classified the procedure into three groups: stand-alone thoracoscopic discectomy (3 cases), thoracoscopic fusion (11 cases) and video assisted mini-thoracotomy (6 cases). Results : Analysis on the Frankel performance scale in spinal trauma patients (13 cases), showed a total of 7 patients who had neurological impairment preoperatively : Grade D (2 cases), Grade C (2 cases), Grade B (1 case), and Grade A (2 cases). Four patients were neurologically improved postoperatively, two patients were improved from C to E, one improved from grade D to E and one improved from grade B to grade D. The preoperative Cobb's and kyphotic angle were measured in spinal trauma patients and were $18.9{\pm}4.4^{\circ}$ and $18.8{\pm}4.6^{\circ}$, respectively. Postoperatively, the angles showed statistically significant improvement, $15.1{\pm}3.7^{\circ}$ and $11.3{\pm}2.4^{\circ}$, respectively(P<0.001). Conclusion : Although VATS requires a steep learning curve, it is an effective and minimally invasive procedure which provides biomechanical stability in terms of anterior column decompression and reconstruction for anterior load bearing, and preservation of intercostal muscles and diaphragm.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.15-28
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• 1995

The GPS positioning involves not only 'natural' errors associated with the satellites position errors, refraction of EM wave in the ionosphere, etc., but also 'artificial' errors associated with the operation of S/A (Selective Availability). In this paper, we present the principles, accuracies and applicabilities of our personal DGPS method, which employs the position-correction method on the GPS positionings data collected at the reference and the remote sites. The essential requirement of our DGPS method is that two GPS receivers should utilize the identical Navstar satellites at the same time. The positioning error (1 drms) of the stand-alone GPS is of an order of a few tens meters, while that of horizontal position by our DGPS method is about 1m and that of vertical position is about 2m We applied out DGPS technique in positioning moving objects, and obtained satisfactory results in tracking the trajectories of a car on the road and the those of drifters in the sea.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.68-72
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• 2004

A practical method to investigate the user interface of web based Flexible Manufacturing System(FMS) on the internet environment is established. Because the industrial FMS controller requires a lot of gadget, such as switch, dial, button, etc., for actual work-site flexible operation sufficiently, the user interface of the controller is significantly complex. The support for operational convenience of FMS controller can increase productivity and efficiency of the user, operational personnel of FMS. While most FMS provide their application programming interface(API) and graphical user interface(GUI) with adequate mechanism itself when used in stand alone, there is increasing demand for FMS that can operate with the intuitional user interface find virtual reality(V/R) environment. This thesis considers the intuitional user interface of Web-based FMS first, and from this, goes a step further, improves as virtual reality environment of FMS on the internet environments by using the feature based modeling technique approach and cartoon rendering. The feature-based modeling technique approach is applied to FMS line which is consist of facilities such as machining center, CNC lathe, autonomous guided vehicle, rail guided vehicle, and various controllers. In this study, the FMS established the intuitional user interface is able to obtain not only the operational convenience but also the enough productivity and significant efficiency.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.155-160
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• 2019

In this paper, we propose an efficient grid-independent ESS control system through the control of renewable energy and agricultural ICT by utilizing the prediction of energy production and consumption. The proposed system is an integrated management system that can perform maintenance and monitoring by visualizing the accurate phase and data of power system. It can automatically cope, collect, process, and control the data. Also, it can analyze the power generation of solar power generation, consumption pattern of installed facilities, and operation trend of facilities. Further, it can predict the consumption of energy production and present the optimal energy management method by using the OpenAPI of the Korea Meteorological Administration, thereby reducing unnecessary energy consumption and operating cost.

• Korea Trade Review
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• v.42 no.5
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• pp.213-232
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• 2017

A Bank Payment Obligation is now in operation as payment instruments in the business of Supply Chain Finance since 2013. The BPO is an irrevocable undertaking of the Obligor Bank subject to the successful electronic matching of all required Data Sets with the established Baseline in the TMA. Although the BPO should be regarded as similar to a Letter of Credit, it is a new payment solution based on a technology and data-driven mechanisms. The BPO is different from the letter of credit in their structure such as a bank to bank obligation, an automated matching engine, a transfer and confirmation of the Credit, etc. The BPO can also be used more effectively on a stand-alone solution as an electronic alternative to the traditional instruments. it will provide a new range of solutions to meet the ever-changing needs of the trade customers. However, the BPO could be raised several issues including an assurance of payment between recipient banks and sellers because the BPO is a bank-to-bank obligation. The URBPO do not applies to the relationships between banks and their business clients. So, the primary objective of this paper is to promote the institutional understanding and present the implications by reviewing the majn issues in the BPO as comparision with the Letter of Credit from the institutional point of view. This research was also based on documentary research focusing on the preceding research and the materials of ICC and SWIFT.

• Korea Trade Review
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• v.43 no.4
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• pp.1-25
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• 2018

Bank payment obligations (BPO) have been used since 2013 as a payment solution in the business of supply chain finance. The BPO is an irrevocable undertaking of the obligor bank subject to the successful electronic matching of all required data sets with the established baseline in the TMA. Although the BPO should be regarded as similar to a letter of credit, it is a new payment solution based on advanced technology and data-driven mechanisms. The BPO differs from the credit in institutional terms such as bank-to-bank obligations, automated matching engines, and transfer and confirmation, etc. The BPO can also be used effectively as a stand-alone electronic solution to traditional instruments. it provides a new range of solutions to meet the ever-changing needs of trade customers. However, Operation of the BPO can leads to several issues including an assurance of payment between recipient banks and sellers because the BPO is a bank-to-bank obligation. The URBPO does not apply to relationships between banks and their business clients. So, the primary objective of this paper is to promote institutional understanding and present implications by reviewing major issues concerning the BPO as compared with the letter of credit from the institutional point of view. This research was based on documentary research focusing on the preceding research and the materials of ICC and SWIFT.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.662-671
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• 2020

Recently, for the purposes of reducing carbon dioxide(CO₂) emissions in the island area, countermeasures to decrease the operation rate of diesel generator(DG) and to increase one of renewable energy sources(RES) is being studied. In particular, the demonstration and installation of stand-alone micro-grid(MG) system which is composed of DG, RES and energy storage system(ESS) has been implemented in some island areas such as Gapa-do, Gasa-do and Ulleung-do island. However, many power quality(PQ) problems may be occurred due to an intermittent output of RES including photovoltaic(PV) system and wind power(WP) system in a normal operating of constant voltage & constant frequency(CVCF) inverter-based MG system. Therefore, this paper presents a modeling of the 30kW scale MG system using PSCAD/EMTDC, and also implements a 30kW scale CVCF inverter-based MG system as test devices to analyze normal operating characteristics of MG system. From the simulation and test results, it is confirmed that the proposed methods are useful and practical tools to improve PQ problems such as under-voltage, over-voltage and unbalanced load in CVCF inverter-based MG system.