• Journal of the Korea Society for Simulation
• /
• v.29 no.2
• /
• pp.73-81
• /
• 2020

HCCL stands for Heterogenous Container Class Library. HCCL is a library that allows heterogeneous types of data to be stored in a container as a single record and to be constructed as a list of the records to be stored in database. With HCCL, encryption/decryption can be done based on the unified data type. Recently, IoT sensor which is embedded in smartphone enables developers to provide various convenient services to users. However, it is also true that infringement of personal information may occur in the process of transmitting sensor information to API and users need to be prepared for this situation in some sense. In this study, we developed a data model that enhances existing security using SEED cryptographic algorithms while managing information of sensors based on HCCL. Due to the fact that the Android environment does not provide permission management function for sensors, this study decided whether or not to encrypt sensor information based on the user's choice so that the user can determine the creation and storage of safe data. For verification of this work, we have presented the performance evaluation by comparing with the situation of storing the sensor data in plaintext.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.7
• /
• pp.629-636
• /
• 2010

A Mobile Harbor is a new transportation platform which can load and unload has containers to and from very large container ships on the sea. Currently designed Mobile Harbor a catamaran type which is equipped with precisely controlled gantry crane on the deck, and can transport 250 TEUs at a time. Loading and unloading works by crane require very small motion of Mobile Harbor in waves, because it may be operated outside of harbors. In this project, applicability of both tuned-type anti-rolling tank and maglev-type active mass driver is studied as anti-rolling systems.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2013.12a
• /
• pp.55-59
• /
• 2013

Transverse vibrations of ship's aft end and deckhouse among the various modes of hull structures are induced mainly by transverse exciting forces and moments of main engine such as ${\times}$ and h-moment. Avoidance of resonance should be made in a intial design stage in case there is a prediction for resonance between main engine and transverse modes of deckhouse. This study shows a case of change in type of main engine from 12 cylinders to 10 without modification of hull structures in engine room requested by a shipowner of 8,600 TEU class container carrier and proposes a guide to the effective ways of structural arrangement for avoiding resonance between transverse exciting force and surrounding structures of main engine in engine room through case studies.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.11a
• /
• pp.185-195
• /
• 2000

This pacer studied on the lateral motion and yaw motion of the gantry crane which is used for the automated container terminal with two driving wheel types. Though several problems are occcurred in driving of gantry crane, they are solved by the motion by the operators. But, if the gantry crane is unmanned, it is automatically controlled without any operation. There are two types, cone and flat t y pin driving wheel shape. In cone type, lateral vibration and yaw motion of crane are issued. In flat type, the collision between wheel-flange and rail or the fitting between wheel-flanges and rail is issued. Especially, the collision between wheel-flange and rail is a very critical problem in driving of unmanned gantry crane. To bring a solution to the problems, the lateral and yaw dynamic equations of the driving mechanism of gantry crane with two driving wheel types are derived. Then, we investigate the driving characteristics of gantry crane. And this study used PD(Proportional-Derivative) Controller to control the lateral displacement and yaw angle of the gantry crane. The simulation result of the driving mechanism using the Runge-Kutta Method is presented in this paper.

• Journal of Bio-Environment Control
• /
• v.21 no.3
• /
• pp.199-206
• /
• 2012

This study was conducted in a glasshouse to examine the possibility of producing tomato plug seedlings in a newly-developed inert phenolic foam medium. Plug seedlings of 'Madison' tomato were grown in four pellet type media, Grodan rockwool, UR rockwool, phenolic foam LC, and phenolic foam LC-lite. Seed germination was checked for 7 days. Seedling growth was measured at 19 days after sowing. The greatest germination was obtained in the phenolic foam LC and phenolic foam LC-lite. Plant height, hypocotyl length, leaf area, dry weight, and fresh weight were significantly greater in the rockwool medium than those in the other media. However, the T/R ratio and stem diameter were the greatest in the phenolic foam LC than those in the other media. The total porosity and container capacity of the phenolic foam LC was higher than in the other media. The air space (%) was lowest in the phenolic foam LC. Overall, the phenolic foam LC and phenolic foam LC-lite produced seedlings with similar growth as the rockwool. These results suggested that both phenolic foam LC and phenolic foam LC-lite have potential to be used in production of plug seedlings of 'Madison' tomato.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.9
• /
• pp.806-813
• /
• 2013

For the past years, higher power rating 2 stroke super long stroke diesel engines having more than 8 cylinders and larger cylinder bore are installed mainly on very large containerships to save on fuel consumption. However, these engines are prone to X-mode vibration due to 2nd node torsional vibration or the X-type moment, particularly because of the increase in total length and height. Recently, cases of excessive X-mode vibration often occurred on engine's major components. This vibration is manifested also as secondary vibration causing failure in engine-mount large structures. This study investigated the excitations caused by the 2nd node propulsion shafting torsional vibration that influence X-mode vibration of the main engine and practical countermeasures are proposed. An 8RT-flex82T 8 cylinder engine and 11S90ME-C 11 cylinder engine for a container ship was used as research model.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.2
• /
• pp.446-454
• /
• 2016

In this paper, we present experimental results of the soil discharge characteristics as a function of moisture content when a 1.2/50-㎲ lightning impulse voltage is applied. For this study, laboratory experiments were carried out based on factors affecting the transient behavior in soils. The electrical breakdown voltages in soils were measured for a 0-6% range of moisture content for sand and a 0 - 4% range of moisture content for gravel. A test cell with semi-spherical electrodes buried face-to-face in the middle of a cylindrical container was used. The distance separating the electrodes is 100 mm. As a result, the time-lag to breakdown in soils decreases as the amplitude of applied voltage increases. The time-lag to initiation of ionization streamer is decreased, with an increase in the moisture content. However, the formative time-lag is rarely changed. The behavior of soil discharges depend not only on the type of soil and its moisture content but also on the amplitude of the impulse voltage. When the test voltage is applied repeatedly, electrical breakdown occurs along different discrete paths, leading radially away from the injected electrode. i.e., the fact that the ionization streamers propagate in different paths from shot to shot was observed.

• Journal of Environmental Science International
• /
• v.28 no.6
• /
• pp.545-552
• /
• 2019

Tropaeolum majus, with a high decorative and food demand for vertical greening systems, has been utilized to revitalize urban agriculture. The effects of number of non-woven fabrics in a non-water environment and the adaptability of T. majus to this system were investigated. Planting ground composition of the container-type wall vertical greening system was made using non-woven fabric in one, two, three, or four layers. The results showed that the soil water content remained the highest when the non-woven fabric comprised 4 sheets. The morphological properties showed more growth with the 4 sheets than with 1, 2, and 3 sheets. In terms of physiological characteristics, chlorophyll content was mostly high in the 4 sheets, while shoot fresh weight value was in the order of 3 > 4 > 2 > 1 sheet, and root fresh weight value was in the order of 4 > 2 > 1 > 3 sheets. The dry weight of the measured values in the shoot was in the order of 4 > 3 > 2 > 1 sheet while no clear difference was found in the root of each treatment. The difference in the flowring characteristics was not different, but in evaluating the characteristics as a whole, the growth in the three layers of non-waven fabric was the best. In addition, the soil moisture contents and the growth characteristics were statistically significant as a positive correlation between the groups. Thus, greater the non-woven fabric, the higher is the adaptability of T. majus to dry stress under soil water-free conditions by maintaining soil moisture content. This showed that it represented an effective alternative as a method of vertical greening system for lower maintenance urban agriculture.