• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.506-512
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• 2018

Unmanned aerial vehicles(UAVs) operating in the military for various purposes are designed to transmit information collected according to the purpose to GCS(Ground Control System), and to transmit/receive the vehicle's operational control and status information using wireless communication(or datalink). Currently, the military UAV systems in operation in Korea use unique communication methods, protocols, and message structures for each system. Among these, the Division UAV is designed to transmit fixed size TM/TC data repeatedly and the Corps UAV is designed to transmit aperiodic TM/TC data to the variable length of the message-based. In this paper, we analyze the TM/TC data protocol of existing military UAV systems and present data protocol design method which is considered to be more efficient in wireless communication environment applied to equipment under development. And we will discuss issues to be considered for standardization of technology for ensuring interoperability with many UAVs or newly introduced UAV systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.466-475
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• 2011

This paper presents development status of sounding rockets containing scientific payload and telemetry at home and abroad. The case of outside, United States is launching sounding rockets in 20-30 flights per year by the NASA program which offers to carry payload weights of 38-680 kg and altitude of 88-1500 km. Europe is launching in 4-5 flights per year by the ESA program. The case of Korean sounding rockets was successful with the launch of three times(KSR-I,II,III), but Korea lags far behind the advanced countries in the field of development technologies for space launch vehicle. We expect that our scientific and industrial technologies will be improved through the research and development of sounding rockets. In this study we proposed necessity and future direction of development in domestic sounding rockets.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.70-79
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• 2011

This paper presents development status of sounding rockets containing scientific payload and telemetry at home and abroad. The case of outside, United States is launching sounding rockets in 20-30 flights per year by the NASA program which offers to carry payload weights of 38-680 kg and altitude of 88-1500 km. Europe is launching in 4-5 flights per year by the ESA program. The case of Korean sounding rockets was successful with the launch of three times(KSR-I,II,III), but Korea lags far behind the advanced countries in the field of development technologies for space launch vehicle. We expect that our scientific and industrial technologies will be improved through the research and development of sounding rockets. In this study we proposed necessity and future direction of development in domestic sounding rockets.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.72-74
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• 2012

위성의 상태를 모니터링하고 임무수행 준비 및 결과를 분석하기 위해 위성에서는 주기적으로 텔레메트리 프레임을 생성하여 지상으로 전송한다. 텔레메트리 프레임을 통해 많은 데이터가 전송될수록 정확한 위성의 상태 분석이 가능하고 위성 운용을 용이하게 할 수 있다. 그러나 위성에서 지상으로 전송할 수 있는 텔레메트리의 전송속도는 하드웨어의 성능에 따라 제한되며, 특히 저궤도 위성의 경우에는 지상과 교신이 가능한 시간이 짧다는 제약으로 인해 한정된 시간 안에 정해진 전송속도로 보낼 수 있는 데이터의 양에는 한계가 있다. 이러한 제약조건 하에서 최대한 많은 정보를 효율적으로 전송할 수 있도록 위성의 텔레메트리를 생성할 때 비트 정보들을 모아 하나의 바이트로 묶어서 텔레메트리 크기를 최소화하는 방법을 이용한다. 위성비행소프트웨어는 태스크 스케쥴링, 열제어, 전력제어, 자세제어, 원격명령처리, 원격측정데이터 처리 등의 기능별로 모듈화 되어있다. 각 모듈마다 텔레메트리로 전송되는 데이터들이 존재하고 비트 정보들을 모으는 기능도 해당하는 모듈에서 각각 담당한다. 따라서 각 모듈들이 독립적이지 못하고 텔레메트리 처리를 담당하는 모듈과 다른 모듈들 간의 커플링(coupling)이 존재하게 되어 하나의 텔레메트리 데이터 변경이 여러 모듈에 영향을 미치게 된다. 본 논문에서는 모듈들 간의 커플링을 최소화하고 텔레메트리의 변경사항이 위성비행소프트웨어 코드 자체에는 영향을 주지 않도록 하기위한 데이터베이스 테이블을 이용한 텔레메트리 처리 방안에 대하여 설명한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1563-1570
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• 2018

Internet of Things technology is rapidly becoming a reality in many parts of our lives through various product services, and product development especially in the field of smart home is being actively carried out. Most controllers for controlling various smart home products use smart phone applications. However, smart phone applications are not suitable as smart home controllers, contrary to smart home services that emphasize intelligence and convenience. In order to provide intelligent smart home service, intuitive form of smart home controller is needed, which enables integrated control of smart home device. Therefore, this paper proposes a smart home remote control that can control the Internet devices and services of objects. The proposed smart home remote control provides an environment where users can build a smart home service through the IFTTT(If This Then That) automated service platform.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1604-1610
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• 2018

The speech recognition service is used as an ancillary means of communication by converting and visualizing the speaker's voice into text to the hearing impaired persons. However, in open environments such as classrooms and conference rooms it is difficult to provide speech recognition service to many hearing impaired persons. For this, a method is needed to efficiently provide it according to the surrounding environment. In this paper, we propose a system that recognizes the speaker's voice and transmits the converted text to many hearing impaired persons as messages. The proposed system uses the MQTT protocol to deliver messages to many users at the same time. The end-to-end delay was measured to confirm the service delay of the proposed system according to the QoS level setting of the MQTT protocol. As a result of the measurement, the delay between the most reliable Qos level 2 and 0 is 111ms, confirming that it does not have a great influence on conversation recognition.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.4
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• pp.283-288
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• 2019

In this paper, there is summarized the validation of ground test results through the telemetry acquired during on-orbit initial activation on solar-array drive assembly(SDA) of GK2A launched at Dec-5, 2018. Especially, the decision logic of SDA initial position and the compensation logic are validated and confirmed. The SDA initial position is needed when GK2A enter to geostationary orbit from transfer orbit and the compensation logic is for the accumulated position error due to the open-loop control. Up to now, it is normal operating. Also the periodic offset between the geostationary orbit and Sun position is found that it is not checked on design phase, and then the proper threshold value is applied.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.217-222
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• 2021

EOTS(Electro-Optical Tracking System) is utilized in acquiring visual information to assess a guided missile's performance. As the missile travels so fast, it is almost impossible for operator to re-capture the lost target. The RADAR or telemetry data are used to re-capture the lost target however facilities to receive real time data is required, which constrains selection of tracking site. Unlike aforementioned data, pre-calculated nominal trajectory can be used without communication facility. This paper proposes a method to predict lost target's state by employing nominal trajectory. Firstly, observed trajectory and nominal trajectory are compared using DTW and current target's state is predicted. The predicted state is used as observation in Kalman filter's correction phase to predict target's next state. The plausibility of the proposed method is verified by applying on actual missile trajectory.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.23-28
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• 2021

The article discusses the features of adaptation of the parameters of the physical layer of data transmission in self-organizing networks based on unmanned aerial vehicles operating in the conditions of "smart cities". The concept of cities of this type is defined, the historical path of formation, the current state and prospects for further development in the aspect of transition to "smart cities" of the third generation are shown. Cities of this type are aimed at providing more comfortable and safe living conditions for citizens and autonomous automated work of all components of the urban economy. The perspective of the development of urban mobile automated technical means of infocommunications is shown, one of the leading directions of which is the creation and active use of wireless self-organizing networks based on unmanned aerial vehicles. The advantages of using small-sized unmanned aerial vehicles for organizing networks of this type are considered, as well as the range of tasks to be solved in the conditions of modern "smart cities". It is shown that for the transition to self-organizing networks in the conditions of "smart cities" of the third generation, it is necessary to ensure the adaptation of various levels of OSI network models to dynamically changing operating conditions, which is especially important for the physical layer. To maintain an acceptable level of the value of the bit error probability when transmitting command and telemetry data, it is proposed to adaptively change the coding rate depending on the signal-to-noise ratio at the receiver input (or on the number of channel decoder errors), and when transmitting payload data, it is also proposed to adaptively change the coding rate together with the choice of modulation methods that differ in energy and spectral efficiency. As options for the practical implementation of these solutions, it is proposed to use an approach based on the principles of neuro-fuzzy control, for which examples of determining the boundaries of theoretically achievable efficiency are given.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.301-311
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• 2021

The technological advancements of the last two decades directed the era of the Internet of Things (IoT). IoT enables billions of devices to connect through the internet and share their information and resources on a global level. These devices can be anything, from smartphones to embedded sensors. The main purpose of IoT is to make devices capable of achieving the desired goal with minimal to no human intervention. Although it hascome as a social and economic blessing, it still brought forward many security risks. This paper focuses on providing a survey of the most commonly used application layer protocols in the IoT domain, namely, Constrained Application Protocol (CoAP), Message Queuing Telemetry Transport (MQTT), Advanced Message Queuing Protocol (AMQP), and Extensible Messaging and Presence Protocol (XMPP). MQTT, AMQP, and XMPP use TCP for device-to-device communication, while CoAP utilizes UDP to achieve this purpose. MQTT and AMQP are based on a publish/subscribe model, CoAP uses the request/reply model for its structuring. In addition to this, the quality of service provision of MQTT, AMQP, and CoAP is not very high, especially when the deliverance of messages is concerned. The selection of protocols for each application is very a tedious task.This survey discusses the architectures, advantages, disadvantages, and applications of each of these protocols. The main contribution of this work is to describe each of the aforementioned application protocols in detail as well as providing their thorough comparative analysis. This survey will be helpful to the developers in selecting the protocol ideal for their system and/or application.