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Worst Case Analysis of Packet Delay in Avionics Systems for Environmental Monitoring
Kyungtae Kang,Min-Young Nam,Lui Sha IEEE 2015 IEEE systems journal Vol.9 No.4
<P>Early analysis of timing is essential in the design of reliable avionics systems. We consider an environmental monitoring system that allows the surroundings of an aircraft to be observed continuously in real time. We analyze timing aspects of the partitions within the sensor and monitoring nodes, and of the intermediate switches that connect them. We use the application-specific I/O integration support tool (ASIIST) to evaluate the worst case delay in the peripheral component interconnect buses of the end nodes. We describe a novel switching algorithm that guarantees a bounded delay for any feasible traffic through each switch, and then derive the worst case delay incurred in a switched network that contains switches operating with the proposed algorithm. By composing these delays, we are able to determine the end-to-end delay over the internal buses and network comprising the entire system, and show how it can be bounded by using our switching algorithm. Our worst case end-to-end delay analysis contributes to more reliable and better verified environmental monitoring services over packet-switched networks in avionics systems. We expect that our work will help reduce the cost of designing and implementing environmental monitoring avionics systems, by making it easier to identify unsatisfactory designs at an early stage.</P>
Kyungtae Park,En Sup Yoon,Jamin Koo,신동일,이창준 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4
A general mathematical programming formulation which also considers safety factors is presented for solving the multi-floor plant layout problem. In the presence of a risk of physical explosion, the safety distance must be considered to generate more reasonable and safe layouts. The proposed method determines detailed multi-floor process plant layouts using mixed integer linear programming (MILP). To consider the safety distance, a consequence analysis is adopted for calculating an equipment physical explosion probit. As the TNT equivalency method is used,more realistic estimations of equipment damage are possible, generating safer plant layouts. The objective function minimizes the layout cost (total plant area, floor construction costs and connection costs) and explosion damage costs for the multi-floor problem. Two illustrative examples are presented to demonstrate the applicability of the proposed method.
Toward energy-efficient error control in 3G broadcast video
Kyungtae Kang,Junhee Ryu,Sunghyun Choi,Kyung-Joon Park,Junbeom Hur IEEE 2012 IEEE wireless communications Vol.19 No.6
<P>Energy use is a key issue in battery-operated mobile devices. In order to extend battery life, mobiles showing video often allow a controlled drop in quality, which is tolerable when the shortcomings of a small screen are combined with the imperfections of visual perception. Both energy consumption and video quality are affected by the Reed-Solomon codes and interleaving levels used in 3G video broadcast services. We explore the effect of these elements of MAC-layer error control, and show how they can be manipulated to save energy while maintaining acceptable video quality through a controlled reduction in the number of parity symbols in the Reed-Solomon code and the level of interleaving.</P>
A Medical-Grade Wireless Architecture for Remote Electrocardiography
Kyungtae Kang,Kyung-Joon Park,Jae-Jin Song,Chang-Hwan Yoon,Lui Sha IEEE 2011 IEEE transactions on information technology in bio Vol.15 No.2
<P>In telecardiology, electrocardiogram (ECG) signals from a patient are acquired by sensors and transmitted in real time to medical personnel across a wireless network. The use of IEEE 802.11 wireless LANs (WLANs), which are already deployed in many hospitals, can provide ubiquitous connectivity and thus allow cardiology patients greater mobility. However, engineering issues, including the error-prone nature of wireless channels and the unpredictable delay and jitter due to the nondeterministic nature of access to the wireless medium, need to be addressed before telecardiology can be safely realized. We propose a medical-grade WLAN architecture for remote ECG monitoring, which employs the point-coordination function (PCF) for medium access control and Reed-Solomon coding for error control. Realistic simulations with uncompressed two-lead ECG data from the MIT-BIH arrhythmia database demonstrate reliable wireless ECG monitoring; the reliability of ECG transmission exceeds 99.99% with the initial buffering delay of only 2.4 s.</P>
Kyungtae Park,Sang Yeob Lee,Boran Ji,Hamin Lee,Bo-Kook Jang,Ju-Sung Cho 한국원예학회 2021 한국원예학회 학술발표요지 Vol.2021 No.10
This study has stored Pulsatilla dahurica (Fisch. ex DC.) Spreng. seeds, which is known to be short in storage life, in various temperatures for one year to observe the changes in germinability and anticipated the appropriate storage temperature by performing accelerated aging experiment. Seeds for storage were collected in Andong-si, Gyeongsangbuk- do, late May 2020 and were sealed in plastic bag after the cleaning and stored in ‒20, 4, and 25°C chamber for one year. Control seeds used for Saturated Salt Accelerated Aging (SSAA) test was collected in early June 2021 at the same place. Each seed had measured of their sizes, weight of one thousand seeds, moisture content, E:S ratio, viability, and 4 weeks of initial percent germination, after the collection. SSAA test was performed using aging tray installed seed testing container with 40mL of saturated salt solution (NaCl). Seeds were aged for 72h at 41 and 47°C then their viability was measured with TZ test and were incubated in the chamber. After one year, germinability of stored seeds were measured with their percent germination (PG), start of germination (SG), mean germination time (MGT) and median germination time (T50) in 25/15°C (16/8h, White-LED, 30 μmol/m<SUP>-2</SUP>/s<SUP>-1</SUP> PPFD/Dark) chamber. As a result, seeds from both lots had E:S ratio of 0.23~0.24 indicating that they are morphologically immature. Initial viability of seed lots was over 98% and the PG had scored 97.5 (2020) and 98.0% (2021). PG of the seeds stored for one year in various temperatures were measured 100 (‒20°C), 98.5 (4°C) and 96.5% (25°C) which had no significant difference. However, SG was reduced to 11.2 (‒20°C), 11.5 (4°C) and 12.8 d (25°C) when compared to 15.0 before the storage. MGT and T50 were also reduced to 9.0 to 9.5 and 10.5 to 11.9 d respectively than the seeds before storage (18.0 and 17.5 d). Viability of SSAA tested stored seeds were 96 and 6 (‒20°C), 97 and 12 (4°C), 58 and 0% (25°C), 90 and 27% (non-stored) at 41 and 47°C respectively. On the other hand, SSAA tested seeds showed lower percent germination value than the measured viability. Percent germination of seeds with accelerated aging at 41°C were 44 (‒20°C), 66 (4°C) and 2% (25°C) which were lower than that of non-stored seeds (80%) and among them, the seeds stored at 4°C showed the highest value. Non-stored seeds with accelerated aging at 47°C showed percent germination of 28% where all the other stored seeds did not germinate. Therefore, the two experiments have confirmed that P. dahurica seeds do not deteriorate in their germinability even after one year of storage and SSAA test have proven that seeds stored at 4°C can preserve the viability relatively longer. Additionally, viability and the actual germinability of aged P. dahurica seeds are found to have some differences.