• Current Research on Agriculture and Life Sciences
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• v.30 no.1
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• pp.27-33
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• 2012

This study was conducted to provide data necessary for clearing up the way to be able to improve covering and management method of covering material in commercial plastic greenhouse. The photosynthetic photon flux(PPF) in representative 4 different commercial tomato greenhouses was measured and analyzed. The variation trend of daily integral PPF was in agreement with that of the duration of sunshine. Each of daily integral PPF for 4 different experimental greenhouses was quite dissimilar, and was less than the amount of PPF necessary to grow tomato. October to November of beginning of winter was a good season to replace covering material in order to secure more PPF during insufficient winter season in greenhouse. The main inside factors to interrupt PPF incidence were thermal screen, inside covering material, condensation receiver in greenhouse. The single wide span greenhouse covered with PO film was superior to the other experimental greenhouses in the aspect of PPF transmittance.

• The KIPS Transactions:PartA
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• v.18A no.6
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• pp.271-280
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• 2011

Time-Triggered Architecture (TTA), one of real-time software design paradigms which executes tasks in timely manner, has long been advocated as being better suited in fore-sighting system behavior than event-triggered architecture (ETA). To gain this valuable feature of TTA, however, precise task designing process is mandatory. Alternatively, ETA tries to execute tasks whenever paired events are occurred. It provides intuitive and flexible basement to add/remove tasks and, moreover, better response time performance. However ETA is difficult to analyze because system behavior might be different depending on the order of interrupts detected by the system. Many previous researches recommended TTA when developing safety-critical real-time systems, but cost problem of task designing process and insufficient consensus for applying rigorous software engineering practice are still challenging in practice. This paper describes software refactoring process which applying TTA approach into ETA based embedded software in artificial heart system. We implemented dedicated interrupt monitoring program to capture existing tasks' real-time characteristics. Based on the captured information, proper task designing process is done. Real-time analysis using RMA (Rate-Monotonic Analysis) verified that new design guarantees timeliness of the system. Empirical experiments revealed that revised design is as efficient, when measured in terms of system's external output, as the old design and enhances predictability of the system behavior as well.

• The KIPS Transactions:PartA
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• v.16A no.6
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• pp.463-472
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• 2009

Real-time operating systems must have satisfying various conditions such as effective scheduling policies, minimized interrupt delay, resolved priority inversion problems, and its applications to be completed within desired deadline. The real-time operating systems, therefore, should be designed and developed to be optimal for these requirements. MicroC/OS-II, a kind of Real-time operating systems, uses the basic priority inheritance with a mutex to solve priority inversion problems. For the implementation of mutex, the kernel in an operating system should provide supports for numerous tasks with same priority. However, MicroC/OS-II does not provide this support for the numerous tasks of same priority. To solve this problem, MicroC/OS-II cannot but using priority reservation, which leads to the waste of unnecessary resources. In this study, we have dealt with new design a protocol, so called TPSP(Temporary Priority Swap Protocol), by an effective solution for above-mentioned problem, eventually enabling embedded systems with constrained resources environments to run applications.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9319-9325
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• 2014

Alkaloids are the most extensively featured compounds of natural anti-tumor herbs, which have attracted much attention in pharmaceutical research. In our previous studies, a mixture of major three alkaloid components (5, 6-dihydrobicolorine, 7-deoxy-trans-dihydronarciclasine, littoraline) from Hymenocallis littoralis were extracted, analyzed and designated as AHL. In this paper, AHL extracts were added to human liver hepatocellular cells HepG-2, human gastric cancer cell SGC-7901, human breast adenocarcinoma cell MCF-7 and human umbilical vein endothelial cell EVC-304, to screen one or more AHL-sensitive tumor cell. Among these cells, HepG-2 was the most sensitive to AHL treatment, a very low dose ($0.8{\mu}g/ml$) significantly inhibiting proliferation. The non-tumor cell EVC-304, however, was not apparently affected. Effect of AHL on HepG-2 cells was then explored. We found that the AHL could cause HepG-2 cycle arrest at G2/M checkpoint, induce apoptosis, and interrupt polymerization of microtubules. In addition, expression of two cell cycle-regulated proteins, CyclinB1 and CDK1, was up-regulated upon AHL treatment. Up-regulation of the Fas, Fas ligand, Caspase-8 and Caspase-3 was observed as well, which might imply roles for the Fas/FsaL signaling pathway in the AHL-induced apoptosis of HepG-2 cells.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.6
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• pp.397-402
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• 2016

To produce adequate electricity in nuclear and thermal power plants, an optimal amount of steam should be supplied to a generator connected to high- and low-pressure steam turbines. A turbine output control device, which is a special steam valve employed to supply or interrupt the steam to the turbine, is operated using a hydraulic servo actuator. In power plants, the performance of servo actuators is degraded by the air generated from the hydraulic system, or causes frequent failures owing to an increase in the wear of the seal. This is due to the seal being burnt as generated heat using the produced compressed air. Some power plants have exhausted air using a fixed orifice, and thus they encounter power loss due to mass flow exhaust. Failures are generated in hydraulic pumps, electric motors, and valves, which are frequently operated. In this study, we perform modeling and analysis of the load-sensing air-exhaust valves, which can be passed through very fine flow under normal use conditions, and exhaust mass flow air at the beginning stage as with existing fixed orifices. Then, we propose a method to prevent failures due to the compressed air, and to ensure the control accuracy of hydraulic servo actuators.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.12-21
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• 2012

IEEE 802.11 MAC protocol standard, DCF(CSMA/CA), is originally designed to ensure the fair channel access between mobile nodes sharing the local wireless channel. It has been, however, revealed that some misbehavior nodes transmit more data than other nodes through artificial means in hot spot area spreaded rapidly. The misbehavior nodes may modify the internal process of their MAC protocol or interrupt the MAC procedure of normal nodes to achieve more data transmission. This problem has been referred to as a selfish node problem and almost literatures has proposed methods of analyzing the MAC procedures of all mobile nodes to detect the selfish nodes. However, these kinds of protocol analysis methods is not effective at detecting all kinds of selfish nodes enough. This paper address this problem of detecting selfish node using Tsallis-Entropy which is a kind of statistical method. Tsallis-Entropy is a criteria which can show how much is the density or deviation of a probability distribution. The proposed algorithm which operates at a AP node of wireless LAN extracts the probability distribution of data interval time for each node, then compares the one with a threshold value to detect the selfish nodes. To evaluate the performance of proposed algorithm, simulation experiments are performed in various wireless LAN environments (congestion level, how selfish node behaviors, threshold level) using ns2. The simulation results show that the proposed algorithm achieves higher successful detection rate.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.181-190
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• 2002

IEEE1394 is a de facto standard for the home network interfaces of digital multimedia home devices including digital A/V systems, digital camcorders, and PCs. Recently, it has been used in applications to guarantee the real-time characteristics such as home automation system and IICP (Instrument and Industrial Control Protocol). In order to guarantee real-time requirements in these IEEE1394-based real-time applications, this thesis proposes the software architecture of an IEEE1394 based home network that supports the guarantee for service's react-time characteristics. The proposed architecture has a real-time IEEE1394 device driver and event service architecture for guarantee real-time characteristics. The real-time device driver supports priority-based queueing of packets and mechanism to reduce the interrupt latency time in ISR. The event service architecture supports a real-time events delivery based on home network service using real-time event channel. This architecture can accommodate the real-time requirements of various applications and services such as digital multimedia services with QoS guarantees. home automation system required real-tine characteristics.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.3-32
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• 2020

With controlling Drones, although it was discussed in the previous study which showed a possibility. Which is personality and property rights of third parties could be violated while operating the drone with a video camera. But It's hard to find out precedents related to drones in Korea. In case of that someone try to control the drone which is equipped with a camera in a yard of neighborhood, the German District Court (Potsdam) considered an operator of drone has little bit of careless to do his duty and admit nonfeasance claim in the owner of the one's property for prevention to repetition of similar situation according to a nonfeasance claim for prevention to Section 1004 (1) sentence 2 of the German Civil Code(BGB). The drone which is equipped with a camera have possibilities to disrupt property and personal rights of the owner. Because a danger in repetition is getting larger regarding the violation of law. Moreover, there is a case that someone shot down the drone which is equipped with a camer. Because it has a risk to interrupt private life and cause some dangerous in our life. The German district court(Riesa) recently have considered that controlling the drone with a camera in private spaces is illegal as a violation of personal life. In addtion to, the action of property owner shot down drone is a legal according to § 228 of the German Civil Code(BGB) which is caleed "Necessity". Although it is difficult to apply to foreign cases directly to Korea, similar cases are likely to be occurred in Korea. The decision of the German District Court showed implications to Korea. As demand for the camera-equipped drone increases in Korea, it is time to discuss specific measures for drone violations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.35-46
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• 2006

When an RFID reader attempts to read the tags, interference might occur if the neighboring readers also attempt to communicate with the same tag at the same time or the neighboring readers use the same frequency simultaneously. These interferences cause the RFID reader collision. When the RFID reader collision occurs, either the command from the reader cannot be transmitted to the tags or the response of the tags cannot receive to the reader correctly, Therefore, the international standard for RFID and some papers proposed the methods to reduce the reader collision. Among those, Colorwave and Enhanced Colorwave is the reader anti-collision algorithm using the frame slotted ALOHA based a TDM(Time Division Multiplex) and are able to reduce the reader collision because theses change the frame size according to a collision probability. However, these can generate the reader collisions or interrupt the tag reading of other readers because the reader that collides with another reader randomly chooses a new slot in the frame. In this paper, we propose a new RFID reader anti-collision algorithm that each reader monitors the slots in the frame and chooses the slot having the minimum occupation probability when the reader collision occurs. Then we analyze the performance of the proposed algorithm using simulation tool.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.77-82
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• 2012

To share the lanes with conventional vehicles, traffic operation strategy is needed for NEV (Neighborhood Electric Vehicle). Because NEV cannot accelerate sharply as fast as common car include gasoline, diesel and LPG cars, they may interrupt traffic conditions and make traffic delay. After green lights turn on, all vehicles run through the street including NEV, but NEV have a maximum speed which is 50km/h. It can be an obstacle for following vehicles and will make traffic delay of the intersection. In this reason, we need to organize traffic systems like queue jump with priority traffic signal. To analyze the necessity for NEV road operations, we simulate three scenarios in congested and non-congested conditions. First is that we examine the condition which is mixed NEV and cars on the road, the second one is that we set up lane only NEV can accepted in simulation and last one is making queue jump lane and providing priority signal for NEV. In conclusion, we can conclude that making lane only for NEV is effective to improve travel speed when rate of NEVs is over 20%. Also queue jump lane and priority signal cannot make good effect to intersection delay and average speed.