• Journal of the Korean Data and Information Science Society
• /
• v.26 no.5
• /
• pp.1141-1154
• /
• 2015

This paper describes the convergence of the energy technology and information and communication technology (ICT), which helps to consume less energy effectively. While a lot of researches have done against the increase of world energy usage, most of them focus on the efficiency of energy supply, transfer, and consumption equipment. Applying the ICT to decrease energy usage could help to find energy saving factors in the new field that has not been considered as a valuable one before. The big data service with the energy technology and ICT convergence enables correlation analyses of large sets of energy and environmental data. Finding a data tendency with a big data service helps to develop energy saving policies. Furthermore, it could make a further step to develop a new business model. This paper introduces the real cases of the company and project that provides a big data service with the ICT convergence.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37B no.12
• /
• pp.1113-1118
• /
• 2012

Smart grid and intelligent transportation system draw significant interest since they are considered as one of the green technologies. These systems require a large number of sensors, actuators, and controllers. Also, machine-to-machine (M2M) communications is important because of the automatic control. The LTE-Advanced networks is preparing a set of functions that facilitate the M2M communications, and particularly the development of an efficient call admission control mechanism is critical. A method that groups MTC devices according to QoS constraints and determines the admission depending on the QoS satisfaction is limitedly applied only if the data transmission period and the maximum delay are identical. This paper proposed a call admission control that is free from such limitation and also optimizes the admission process under the certain condition of the transmission period and maximum delay. The theorems regarding the proposed method are presented with the proofs. The simulations confirms its validity and shows it is better in call admission probability than existing works.

• The Korean Journal of Applied Statistics
• /
• v.26 no.6
• /
• pp.1033-1041
• /
• 2013

In this paper, we investigate several variance estimators for pps systematic sampling. Unfortunately, there is no unbiased variance estimators for a systematic sample because systematic sampling can be regarded as a random selection of one cluster. This study provides guidance on which variance estimator may be more appropriate than others in several circumstances. We judge the efficiency of variance estimators for systematic sampling based on of their relative biases and relative mean square error. Also, we investigate variance estimation problems for two-stage systematic sampling applied for the Food Raw Material Consumption Survey and the Establishment Labor Force Survey simulation study, in order to consider the popular two-stage pps systematic sample design for establishment and household survey in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.4B
• /
• pp.219-226
• /
• 2012

In wireless sensor networks (WSNs), location-based multicast routing (LMR) technique can increase the network life time and the channel capacity by reducing the number of duplicated data transmissions and control messages. However, previous LMR techniques can suffer from significant performance degradation due to concrete walls or other interfering objects deployed in the real environment, since they transmit the packets by using only the locations of the sensor nodes. To solve this problem, we propose an interference-aware location based multicast algorithm for WSNs. In the proposed algorithm, each node adjusts the energy cost for each link adaptively considering the interference effect and uses it for multicast decision in order to minimize the interference impact. Experimental results show that the proposed algorithm improves the delivery and energy performance when the network is affected by interference.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.7
• /
• pp.949-955
• /
• 2018

Hardware-in-the-loop (HIL) simulation is a technique that can be employed for developing and testing complex real-time embedded systems. HIL simulation provides an effective platform for verifying power management system (PMS) performance of liquefied natural gas carriers, which are high value-added vessels such as offshore plants. However, HIL tests conducted by research institutes, including domestic shipyards, can be protracted. To address the said issue, this study proposes a field programmable gate array (FPGA) based PMS-HIL simulator that comprises a power supply, consumer, control console, and main switchboard. The proposed HIL simulation platform incorporated actual equipment data while conducting load sharing PMS tests. The proposed system was verified through symmetric, asymmetric, and fixed load sharing tests. The proposed system can thus potentially replace the standard factory acceptance tests. Furthermore, the proposed simulator can be helpful in developing additional systems for vessel automation and autonomous operation, including the development of energy management systems.

• Smart Media Journal
• /
• v.7 no.2
• /
• pp.40-46
• /
• 2018

The conventional CCTV surveillance system for preventing accidents and incidents misses 95% of the data after 22 minutes where one person monitors multiple CCTV. To address this issue, researchers have studied the computer-based intelligent video surveillance system for notifying people of the abnormal situation. However, because the system is involved in the problems of power consumption and costs, the intelligent video surveillance system based on embedded modules has been studied. This paper implements the intelligent video surveillance system based on embedded modules for detecting intruders, detecting fires and detecting loitering, falling. Moreover, the algorithm and the embedded module optimization method are applied to implement real-time processing. The intelligent video surveillance system based on embedded modules is implemented in Raspberry Pi. The algorithm processing time is 0.95 seconds on Raspberry Pi before optimization, and 0.47 seconds on Raspberry Pi after optimization, reduced processing time by 50.52%. Therefore, this suggests real processing possibility of the intelligent video surveillance system based on the embedded modules is possible.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.802-802
• /
• 2012

물발자국은 개인이나 지역, 집단 등이 소비하는 재화와 서비스를 생산하는데 필요한 물의 총량을 나타낸다. 물발자국은 실제 눈에 보이지 않지만 생산품에 내포되는 수자원으로서 농 축산물의 국가간 교역시 가상수의 흐름이 내포되어 있고, 이에 따라 국가별, 품목별로 농 축산물 수출입에 따른 물발자국이 산정될 수 있다. 농 축산물의 물발자국은 농업용수와 관계가 있기 때문에 수출입 정책과 농업용수 수자원 확보를 동시에 고려하기 위하여 주요 농 축산물에 대한 국가간 가상수의 흐름을 분석하고, 이에 따른 국내의 물발자국의 영향을 살펴볼 필요가 있다. 이에 본 연구에서는 농 축산물 교역을 통하여 이동되는 가상수의 흐름과 양을 산정하고 국내의 내적, 외적 물발자국의 변화를 분석하고자 하였다. 먼저 과거 5년 이상의 국가간 농 축산물의 교역량을 조사하고, 주요 농 축산물에 대한 가상수량을 적용하여 국가별, 품목별 Green, Blue, Grey 물발자국을 각각 산정하고 비교하였다. 특히 Blue water는 인위적으로 공급되는 용수이므로 수자원 절약의 측면에서 중요한 의미를 지니고 있다. 다음으로 주요 농 축산물의 국가간 물발자국 산정결과를 통하여 우리나라의 내적, 외적 물발자국을 산정하였다. 내적 물발자국은 자국내에서 생산되는 농 축산물의 가상수를 의미하고, 외적 물발자국은 수입되는 농 축산물에 대한 가상수를 의미한다. 내적, 외적 물 발자국의 비교를 통하여 품목별로 우리나라의 수자원 의존도 등을 평가할 수 있다. 본 연구결과는 단순히 농 축산물의 교역이 물품의 흐름이 뿐만 아니라 물품에 포함되는 가상수의 흐름을 동시에 고려한 것으로서 향후 농 축산물 수출입 정책과 수자원 정책을 동시에 고려하는 농축산업 관련 정책 수립시 중요한 기초자료로서 활용될 수 있을 것으로 판단된다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.19 no.4
• /
• pp.265-271
• /
• 2014

We performed dilution experiments together with copepod added incubations to examine the influence of mesozooplankton on the grazing pressure of planktonic ciliates in Sihwa lake during summer when the abundances of phytoplankton and mesozooplankton increased considerably. Planktonic ciliates consumed 104% of primary production in a day on dilution experiments. However, the ciliates consumption on phytoplankton was reduced to 19% in copepod incubations with Acartia sinjiensis added. This was due to selective predation of A. sinjiensis on oligotrich ciliates ($>20{\mu}m$) which were major grazers on nano-phytoplankton. Our experiments show that grazing pressure of planktonic ciliates based on dilution experiments may be overestimated when the abundance of planktonic ciliates is strongly controlled by copepods. We postulate that the role of planktonic ciliates as grazers could diminish in Sihwa lake in spring and summer when abundance of copepods increase considerably. We suggest that the predation of mesozooplankton should be considered to better appraise the role of planktonic ciliates as grazers.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.9
• /
• pp.617-625
• /
• 2009

NAND flash memory is widely used in embedded systems because of many attractive features, such as small size, light weight, low power consumption and fast access speed. However, it requires garbage collection, which includes erase operations. Erase operation is very slow. Besides, the number of the erase operations allowed to be carried out for each block is limited. The proposed garbage collection method focuses on minimizing the total number of erase operations, the deviation value of each block and the garbage collection time. NAND flash memory consists of pages of three types, such as valid pages, invalid pages and free pages. In order to achieve above goals, we use a page rate to decide when to do garbage collection and to select the target victim block. Additionally, We implement allocating method and group management method. Simulation results show that the proposed policy performs better than Greedy or CAT with the maximum rate at 82% of reduction in the deviation value of erase operation and 75% reduction in garbage collection time.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.7
• /
• pp.100-106
• /
• 2015

In this paper, we propose a fast algorithm for low-power image enhancement method for mobile LCD. In the proposed fast algorithm, the spatial resolution of the input image is significantly reduced, and the image characteristics are analyzed on the reduced resolution image to find a dimming rate adaptive to the image content, thereby saving power. The proposed fast adaptive dimming and image enhancement algorithm is implemented as an application that runs on an Android device. Image quality evaluation and running time analysis experiments on the device indicate that the proposed fast algorithm jointly minimizes the quality degradation and power consumption, reducing the required computation load by over 95%.