• KIPS Transactions on Computer and Communication Systems
• /
• v.6 no.11
• /
• pp.445-452
• /
• 2017

Electric pole is a supporting beam used for power transmission/distribution which accelerometer are used for measuring a external force. The meteorological condition has various effects on the external forces of electric pole. One of them is the elasticity change of the aerial wire. It is very important to perform modelling. The acceleration sensor is converted into a pitch and a roll angle. The meteorological condition has a high correlation between variables, and selecting significant explanatory variables for modeling may result in the problem of over-fitting. We constructed high deviance explained model considering multicollinearity using the Generalized Additive Model which is one of the machine learning methods. As a result of the Variation Inflation Factor Test, we selected and fitted the significant variable as temperature, precipitation, wind speed, wind direction, air pressure, dewpoint, hours of daylight and cloud cover. It was noted that the Hours of daylight, cloud cover and air pressure has high explained value in explonatory variable. The average coefficient of determination (R-Squared) of the Generalized Additive Model was 0.69. The constructed model can help to predict the influence on the external forces of electric pole, and contribute to the purpose of securing safety on utility pole.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.9
• /
• pp.1840-1846
• /
• 2011

It is necessary to estimate the Doppler spectrum for each range cell for the extraction of useful information from the return echoes in radar systems used for the remote sensing purpose such as detection of moving targets and weather surveillance. The signal amplitude in the beat frequency band is the important parameter in the detection and tracking of targets. However, strong clutter echoes do exist in most radar operation environments and the system phase noise spreads both the clutter and signal echoes of the target. In this paper, the effects of this system phase noise are analyzed concerning the clutter and the signal beat spectrum. It is shown that the separation capability of adjacent beat signal depends on the degree of spread in the clutter and beat signal caused by the radar system phase noise

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.605-608
• /
• 2009

It is necessary to estimate the Doppler spectrum for each range cell for the extraction of useful information from the return echoes in radar systems used for the remote sending purpose. However, The conventional spectrum estimation method, FFT(Fast Fourier Transform), called the Doppler filter bank, causes the frequency resolution problem if the dwell time is relatively short. This short acquisition time also spreads the side lobe levels of return echoes further, resulting in difficulties for the discrimination of weak target signals included in relatively strong target echoes. Therefore, in this paper, the efficient Doppler spectrum estimation methods are compared and investigated through the parameter spectrum estimation in the time domain to overcome these problems.

• Journal of Internet of Things and Convergence
• /
• v.9 no.1
• /
• pp.57-64
• /
• 2023

In this paper, we propose a smart umbrella stand based on the Internet of Things (IoT) that helps people to pack their umbrellas more easily. The proposed smart umbrella stand offers three functions. First, it receives weather information, and a hidden umbrella handle will automatically become visible when it rains, making it easier to grab. Second, the smart umbrella stand is equipped with a heated air system, allowing it to effectively dry umbrellas that have become wet due to rain. This makes it more convenient for users to dry and store their rain-soaked umbrellas. Third, the smart umbrella stand enables users to monitor its current status, track weather conditions, and monitor the water level in the rain gutter through a dedicated application. The proposed smart umbrella stand aims to bring convenience to daily life by making it more convenient to carry an umbrella on rainy days or days with a high probability of rain.

• Smart Media Journal
• /
• v.6 no.3
• /
• pp.83-88
• /
• 2017

The data analysis system using Big-data is worthy to be used in various fields such as politics, traffic, natural disaster, shopping, customer management, medical care, and weather information. Particularly, the analysis of the momentum of an individual using an acceleration signal collected from a wearable device has already been widely used. However, since the data used in such a system stores only the data necessary for measuring the individual activity, it does not provide various analysis results other than the exercise amount of the individual. In this paper, I propose a system that analyzes collective behavior pattern and activity based on the acceleration signal that can be collected from personal smartphones for 24 hours a day and stored in big data. I also propose a system that sends acceleration signals and receives analysis results using standard messaging to use on various smart devices.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.12
• /
• pp.1292-1299
• /
• 2014

Weather radar systems can provide weather information of the ground, sea, and air in extensive spatial coverage in near real time. However, it becomes problematic when ground clutter signal exists around precipitation because strong signals of ground can cause a false precipitation report. A large percentage of land coverage of Korea consists of mountainous regions where ground clutter needs to be mitigated for more accurate prediction. Thus, it is considered necessary to introduce a new suitable ground clutter removal technique specifically adequate for Korea. In this paper, the C-Map(Clutter Map) method using raw radar signals is proposed for removing ground clutter using a terrain-adaptive clutter map. A clutter map is generated using raw radar signals(I/Q) of clear days, then it is subtracted from received radar signals in frequency domain. The proposed method is applied to the radar data acquired from Sobaeksan rain radar and the result shows that the clutter rejection ratio is about 91.17 %.

• The KIPS Transactions:PartA
• /
• v.8A no.4
• /
• pp.429-438
• /
• 2001

GPS (Global Positioning System) is the most ideal navigation system which can be used on the earth irrespective of time and weather conditions. GPS has been used for various applications such as construction, survey, environment, communication, intelligent vehicles and airplanes and the needs of GPS are increasing in these days. This paper deals with the design and implementation of the RTOS (Real-Time Operating System) for a GPS navigation computer in the GPS/INS integrated navigation system. The RTOS provides the optimal environment for execution and the base platform to develop GPS application programs. The key facilities supplied by the RTOS developed in this paper are priority-based preemptive scheduling policy, dynamic memory management, intelligent interrupt handling, timers and IPC, etc. We also verify the correct operations of all application tasks of the GPS navigation computer on the RTOS and evaluate the performance by measuring the overhead of using the RTOS services.

• Journal of Satellite, Information and Communications
• /
• v.8 no.1
• /
• pp.14-22
• /
• 2013

GPS radio occultation is a remote sensing technique probing atmospheric properties based on the fact that GPS signal is refracted and delayed by atmosphere. The FORMOSAT-3/COSMIC mission jointly developed by the USA and Taiwan is providing about 2500 occultation soundings a day on the near real-time basis. The Korean KOMPSAT-5/AOPOD system is preparing to launch for monitoring troposphere and ionosphere using a dual frequency GPS receiver and the antenna for occultation data acquisition. In this paper, we examine the methods for signal processing and the geometry analysis for GPS radio occultation, and look into the retrieval techniques for the temperature and humidity of troposphere and the electron density and scintillation of ionosphere. Using these atmospheric properties, we aim to derive the strategies for applying GPS radio occultation to space weather, for example, ionospheric TEC(total electron content) analysis for earthquake monitoring and the Open API(application programming interface) development for more effective data service.

• The KIPS Transactions:PartC
• /
• v.13C no.1 s.104
• /
• pp.95-102
• /
• 2006

Nowadays, GPS is used widely, especially in case which needs precise position information, such as car navigation systems and various kinds of position measuring instruments in an outdoor environment. According to their applications, there are many kinds of GPS receivers with different costs and error rates. The maximum error range of the general-purpose GPS receiver is within 30m, though the error rate depends on receiving rate of signal and weather condition. RTK(Real-Time Kinematic) and DGPS(Differential Global Positioning System) have more precise accuracy than the general-purpose GPS. However end users can't afford use them because of their high price and large size of equipments. In order for the end user to obtain precise position information, it is important that GPS receivers has portability and low price. In this study, we introduce a new system that offers precise position information using the DGPS mechanism satisfying low cost and portability.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.12
• /
• pp.2911-2916
• /
• 2015

The CCTV is limited by weather conditions. To overcome this limitation, we develop a monitoring program that can sense the approach or recede of two or more objects within a surveillance system that uses a continuous-wave (CW) Doppler radar, and we proposed an algorithm to efficiently detect the approach or recede information of the object. The proposed algorithm separates the signal received by the CW Doppler radar into the real and imaginary parts using Fast Fourier Transform (FFT), and sums the amplitudes for each frequency to determine whether the objects are approaching or receding, using their locations. The algorithm is verified by simulations and experiments, which confirms that it successfully detects the approach or recede of two objects.