• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.17-25
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• 2000

ATM PON system is regarded as a solution of the next generation access network because it can cover various types of subscribers in a single platform. In this paper, we describe the merit of the ATM PON and the key protocols for its operation. Above all, the ranging is the most important protocol providing a mean of the time-division multiple access in the system. A problem in the protocol is that the window size, the time interval that ranging cell arrives, is too long. During the interval, user traffics cannot be send to the upstream, which makes the quality of service degraded. In this paper, we suggest a method to minimize the window size when the length of the optic fiber is known with some deviation. The window size can be reduced as 7 % of the conventional method when the deviation of the length is 1 Km.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.520-528
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• 2000

he speed of microprocessor getting faster, the data transfer width between the microprocessor and the memory becomes a critical part to limit the system performance. So the study of the computer architecture with the high code density is cmerged. In this paper, a tentative Bi-Length Instruction Set Computer(BISC) that consists of 16 bit and 32 bit length instructions is proposed as the high code density 32 bit microprocessor architecture. The 32 bit BISC has 16 general purpose registers and two kinds of instructions due to the length of offset and the size of immediate operand. The proposed 32 bit BISC is implemented by FPGA, and all of its functions are tested and verified at 1.8432MHz. And the cross assembler, the cross C/C++ compiler and the instruction simulator of the 32 bit BISC are designed and verified. This paper also proves that the code density of 32 bit BISC is much higher than the one of traditional architecture, it accounts for 130~220% of RISC and 130~140% of CISC. As a consequence, the BISC is suitable for the next generation computer architecture because it needs less data transfer width. And its small memory requirement offers that it could be useful for the embedded microprocessor.

• The KIPS Transactions:PartA
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• v.10A no.3
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• pp.199-206
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• 2003

The object-oriented (OO) distributed real-time (RT) programming movement started in 1990´s and is growing rapidly at this turn of the century. Distributed real-time simulation is a field in its infancy but it is bounded to receive steadily growing recognition for its importance and wide applicability. The scheme is called the distributed time-triggered simulation scheme which is conceptually simple and easy to use but widely applicable. A new generation object oriented (OO) RT programming scheme is called the time-triggered message triggered object(TMO) programming scheme and it is used to make specific illustrations of the issues. The TMO structuring scheme is a general-style components structuring scheme and supports design of all types of component including hard real time objects and non real time objects within one general structure.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.5
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• pp.49-57
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• 2020

Conventional electric motors are not suitable for aircraft because of their large size and weight. High-temperature superconducting (HTS) motors have high current density, high magnetic field density, and low loss, so they can significantly reduce the size and weight compared to general electric motors. This paper presents the conceptual design and analysis results of HTS motors for electric propulsion in future aircraft. A 2.5 MW HTS motor with a rotational speed of 7,200 RPM was designed and the specific power (kW/kg) was analyzed. The operating temperature of the field coil of the HTS motor is 20K in consideration of LH2 cooling. The stator winding were connected in a multi-phase configuration and Litz wires were used to minimize eddy current losses. As a result, it was confirmed that the specific power of the motor is about 18.67 kW/kg, which is much higher than that of the conventional electric motor.

• The KIPS Transactions:PartD
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• v.17D no.6
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• pp.383-394
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• 2010

Flash memory based SSDs are currently being considered as a promising candidate for replacing hard disks due to several superior features such as shorter access time, lower power consumption and better shock resistance. However, SSDs have different characteristics from hard disk such as difference of unit and time for read, write and erase operation and impossibility for over-writing. Because of these reasons, SSDs have disadvantages on hard disk based systems, so FTL(Flash Translation Layer) is designed to increase SSDs' efficiency. In this paper, we propose an advanced logical address mapping method for increasing SSDs' performance, which is named HAMM(Hybrid Address Mapping Method). HAMM addresses drawbacks of previous block-mapping method and super-block-mapping method and takes advantages of them. We experimented our method on our own SSDs simulator. In the experiments, we confirmed that HAMM uses storage area more efficiently than super-block-mapping method, given the same buffer size. In addition, HAMM used smaller memory than block-mapping method to construct mapping table, demonstrating almost same performance.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.218-237
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• 2018

The purpose of this study is to propose a mid - range low - orbit water disaster monitoring satellite development plan to revolutionize water disaster management infrastructure through securing an independent and leading observation infrastructure and to secure safety against disaster prepared for climate change. Water and water disaster satellites should be able to detect changes in the surface of the ground and observe hydrological factors during daytime, nighttime, and bad weather. In addition, independent technology development should be possible. To do this, we selected C-band image radar payload considering domestic technology and water resources management, and suggested detailed development plan. In this way, it is reflected in the national next-generation mid-satellite 2-phase project plan to secure the basis for building a disaster monitoring system related to wide-area water.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.975-980
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• 2019

In this paper, we propose a deep learning-based scheduling scheme for user selection in multi-user multi-antenna networks which is considered one of key technologies for the next generation mobile communication systems. We obtained 90,000 data samples from the conventional optimal scheme to train the proposed neural network and verified the trained neural network to check if the trained neural network is over-fitted. Although the proposed neural network-based scheduling algorithm requires considerable complexity and time for training in the initial stage, it does not cause any extra complexity once it has been trained successfully. On the other hand, the conventional optimal scheme continuously requires the same complexity of computations for every scheduling. According to extensive computer-simulations, the proposed deep learning-based scheduling algorithm yields about 88~96% average sum-rates of the conventional scheme for SNRs lower than 10dB, while it can achieve optimal average sum-rates for SNRs higher than 10dB.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.443-449
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• 2019

To protect the patient's internal organs when a patient with cardiovascular disease occurs, it is important to reduce the elapsed time by providing emergency medical services. Decisions for conducting cardiopulmonary resuscitation are mainly made using the carotid palpation method, which directs the pulse of the carotid artery, which can diagnose the patient's condition according to one's own subject and cause cerebral blood flow to be blocked by excessive pressure in the carotid due to the weaken cardiopulmonary function. In this study, we developed a multimodal patch-type probe based on multi-channel ultrasound Doppler pairs and oxygen saturation measurement modules which can monitor cardiopulmonary functions. From the in-vivo experiments, the developed probe can be utilized as a novel tool that can increase the survival rate of cardiovascular disease patients by objectively monitoring the cardiopulmonary function of the patient quantitatively and promptly in an emergency situation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.99-99
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• 2019

한국생명공학연구원 해외생물소재센터는 해외생물소재 확보 및 활용연구를 통하여 차세대 국가핵심전략 BT산업의 필수원자재인 생물소재의 범지구적 확보와 보존 관리의 임무를 수행하고 있다. 이를 위해 권역별 해외생물소재 공동연구센터(중국, 코스타리카, 인도네시아, 베트남) 및 37개국과의 국제협력 네트워크를 구축하고 있다. 세계적 수준의 생물소재 국가 인프라 구축을 목표로 국내 산 학 연 연구자들에게 다양한 해외생물소재 공급을 통한 지속 가능한 바이오 경제 기반 구축을 지원하고 있다. 해외생물소재센터에서는 2006년부터 특히 천연물 의약품 개발 분야에 많이 사용 되고 있는 해외 식물소재를 지속적으로 확보하고 있으며, 확보된 식물소재의 추출물 제조 및 추출물 은행을 구축, 이에 대한 생물활성 평가를 실시하며 연구자들에게 기초 자료로 제공하고 있다. 현재까지 총 36,500종의 해외식물소재를 확보하였으며, 추출물 약 320만점을 확보하였다. 확보된 소재의 분양활동을 통해 산 학 연 연구자들에게 180만여 점을 분양하였으며, 이를 활용한 다수의 논문과 특허를 획득하였고 중대형 기술이전을 실시하였다. 해외생물소재센터는 홈페이지 기반 분양 신청 시스템[https://www.ibmrc.re.kr]을 통하여 해외식물소재(Powder 와 Extact 형태) 분양서비스를 제공하고 있다. 또한 소재가치제고 연구를 통한 산업화 지원과 해외생물소재의 표본정보 서비스, 해외거점센터를 활용한 현지정보 제공 서비스를 지원하고 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.212-215
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• 2019

지난 4월4일 고성 산불로 사망자 2명과 부상자 1명, 가옥 500여 채, 삼림 1757ha가 불에 탔다. 강원 산불에 이어 영덕지진 등에서 늑장대응을 보여준 재난방송시스템에는 많은 국민들에게 실망감을 안겨주었다. 재난방송 주관방송사인 KBS는 물론, MBC, SBS의 경우도 재난방송시스템에 관련 된 측면에서 본다면 아직 이웃나라 인 일본에 비해서는 매우 열악한 형편이다. 그럼에도 불구하고 점점 대형화, 다발화 하는 재난발생에 대응하기 위해서는 국가적인 차원에서도 특단의 조치가 필요하다. 미국의 경우는 차세대 재난정보 전달체계인 IPAWS(Integrated Public Alert and Warning System)를 개발해 지상파뿐만 아니라, 케이블TV, SNS 등 다양한 매체를 통해 재난정보를 신속하게 전달하고 있다. 일본도 이와 유사한 재난경보전달시스템인 J-Alert를 개발해 2020년까지는 '재난 약자 제로(Zero)시대'를 목표로 구현하고 있다. 우리나라는 지난 아현동 KT 화재사건에서도 경험했듯이 통신이 먹통이 되는 통신블랙아웃도 경험했다. 따라서 대형재난발생 시는 신속한 재난경보전달시스템이 재난피해를 줄일 수 있는 가장 중요한 생명줄이 될 수 있다. 미국이나 일본의 경우는 재난방송전달시스템을 관련법령으로 제도화 하고 있다. 특히, 일본에는 재난에 관한 모법이라고 할 수 있는 (1)"재해대책기본법"이 있는데, 이는 재해로부터 국토, 국민의 생명과 재산을 보호하기 위한 기본법으로 규정되어 있다. 그 밖에도 (2)방송법 (3)대규모지진대책특별 조치법 (4)국민보호법 (5)소방조직법 (6)수해방지법 등으로 규정하고 있다. 과거 일본도 우리나라와 같이 대형 산불이 잦았으나 요즘은 소형 산불만 발생하는 추세다. 이는 NHK가 보유한 700여 대의 로봇카메라와 전 국토를 샅샅이 감시하는 CCTV 덕택이다. 또한, NHK 보도국의 '기상 재해센터'는 재난에 대비해 40여 명의 전문 인력이 24시간 대응체제를 갖추고 있다. 나아가 NHK는 전국 12개의 거점지역에 헬리콥터 15대를 배치하여 신속하게 취재하고 있다. 이 뿐만 아니라, 46개의 지역방송국을 7개의 거점방송국으로 분할하여, 거점방송국마다 40여명의 카메라맨을 상주시켜 언제든지 재난을 취재할 수 있도록 하고 있다. 세계 각국에서 사용하고 있는 방송 주파수는 공공재(公共材)다. 국제전기통신연합(ITU : International Telecommunication Union)으로부터 주파수를 할당받아 사용하고 있기 때문에 주파수에 관한 사용 권한은 각국의 국민 모두에게 있다. 그러나 효과적인 주파수 활용을 전제로 정부가 일정한 자격을 갖춘 방송사업자에게 일시적으로 주파수 사용권을 위임하고 있다. 따라서 일본 정부도 국가적인 위기나 대형 재난발생으로 국민들의 생명과 재산이 위협받고 있을 때에는 공공재인 주파수를 즉시 재난방송으로 사용할 수 있도록 <재해대책기본법 제6조>와 방송법 제108조에 규정하고 있다.