• Journal of Korean Port Research
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• v.11 no.2
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• pp.191-202
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• 1997

As the suitability of berth allocation will ultimately have a significant influence on the performance of a berth, a great deal of attention should be given to berth allocation. Generally, a berth allocation problem has conflicting factors between servers and users. In addition, there is uncertainty in great extent caused by various factors such as departure delay, inclement weather on route, poor handling equipment, a lack of storage space, and other factors contribute to the uncertainty of arrival and berthing time. Thus, it is necessary to establish berth allocation planning which reflects the positions of interested parties and the ambiguity of parameters. For this, a berth allocation problem is formulated by fuzzy 0-1 integer programming introducing the concept of maximum Position Shift(MPS). But, the above approach has limitations in terms of computational time and computer memory when the size of problem is increased. It also has limitations with respect to the integration of other sub-systems such as ship planning system and yard planning system. For solving such problem, this paper focuses particularly on developing an efficient heuristic algorithm as a new technique of getting an effective solution. And also the suggested algorithm is verified through the illustrative examples and empirical appalicaton to BCTOC.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.165-176
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• 1996

Hand posture and force, which define aspects of the way an object is grasped, are features of robotic manipulation. A means for specifying these grasping "flavors" has been developed that uses an instrumented glove equipped with joint and force sensors. The new grasp specification system is being used at the Pennsylvania State University (Penn State) in a Virtual Reality based Point-and-Direct (VR-PAD) robotics implementation. In the Computer Integrated Manufacturing (CIM) Laboratory at Penn State, hand posture and force data were collected for manipulating bricks and other items that require varying amounts of force at multiple pressure points. The feasibility of measuring desired grasp characteristics was demonstrated for a modified Cyberglove impregnated with FSR (Force Sensitive Resistor) pressure sensors in the fingertips. A joint/force model relating the parameters of finger articulation and pressure to various lifting tasks was validated for the instrumented "wired" glove. Operators using such a modified glove may ultimately be able to configure robot grasping tasks in environments involving hazardous waste remediation, flexible manufactruing, space operations and other flexible robotics applications. In each case, the VR-PAD approach improved the computational and delay problems of real-time multiple- degree-of-freedom force feedback telemanipulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.2-5
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• 2021

With the recent development of the Internet of Things (IoT) technology, various terminals are being connected to the Internet. As a result, the amount of IoT data is also increasing, and an index key that can efficient analyze the large-scale IoT data is proposed. Existing index keys have only time and space information, so if data stored in index tables and instance tables were queried using repetition or join operation, IoT data was embedded in the index key of the proposal to create OLAP-based big tables to minimize the number of repetitions or join times.

• The Journal of Korea Robotics Society
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• v.19 no.2
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• pp.139-148
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• 2024

In this paper, we propose a two-degree-of-freedom snake robot head system and an I-PID (Intelligent Proportional-Integral-Derivative)-based controller utilizing RBF (Radial Basis Function) neural network and adaptive robust terms as a control strategy to reduce rotation occurring in the snake robot head. This study proposes a two-degree-of-freedom snake robot head system to avoid complex snake robot dynamics. This system has a control system independent of the snake robot. Subsequently, it utilizes an I-PID controller to implement a control system that can effectively manage rotation at the snake robot head, the robot's nonlinearity, and disturbances. To compensate for the time delay estimation errors occurring in the I-PID control system, an RBF neural network is integrated. Additionally, an adaptive robust term is designed and integrated into the control system to enhance robustness and generate control inputs responsive to signal changes. The proposed controller satisfies stability according to Lyapunov's theory. The proposed control strategy was tested using a 9-degreeof-freedom snake robot. It demonstrates the capability to reduce rotation in Lateral undulation, Rectilinear, and Sidewinding locomotion.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.1
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• pp.63-73
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• 2024

NeQuick G is the ionosphere model utilized by Galileo single-frequency users to estimate the ionospheric delay on each user-satellite link. The model is characterized by the effective ionization level (Az) index, determined by a modified dip latitude (MODIP) and broadcast coefficients derived from daily global space weather observations. However, globally fitted Az coefficients may not accurately represent ionosphere within local area. This study introduces a method for regional ionospheric modeling that searches for locally optimized Az coefficients. This approach involves fitting TEC output from NeQuick G to TEC data collected from GNSS stations around Korea under various ionospheric conditions including different seasons and both low and high solar activity phases. The optimized Az coefficients enable calculation of the Az index at any position within a region of interest, accounting for the spatial variability of the Az index in a polynomial function of MODIP. The results reveal reduced TEC estimation errors, particularly during high solar activity, with a maximum reduction in the RMS error by 85.95%. This indicates that the proposed method for NeQuick G can effectively model various ionospheric conditions in local areas, offering potential applications in GNSS performance analyses for local areas by generating various ionospheric scenarios.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.67-73
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• 2013

This study investigated the quality changes of Samgyetang during storage, resulting from various degassing methods used at the packaging stage. Three different samples were prepared, one without any treatment (CON), a second with reduced head space volume by squeezing the pouch (RHS), and a third by flushing with nitrogen gas (NGF). These were retorted at $120^{\circ}C$ for 65 min under the F-value of approx. 8.0, and stored at $25^{\circ}C$ for 9 months. The oxygen ratio in the head space and the dissolved oxygen content of NGF samples tended to be lower than those of other samples over the storage period. Compared to the CON, the acid values of NGF and RHS samples were lower than the CON from month 3 and 6 (p<0.05). During storage, volatile basic nitrogen values of NGF and RHS samples increased slowly compared to the CON. To delay quality deterioration and extend the shelf-life of Samgyetang products, the reduction of oxygen content in the head space of the retort pouch (preferably by flushing with nitrogen gas) is recommended, even though no significant differences in sensory evaluation were observed among the samples during 9 months of storage (p>0.05).

• Fire Science and Engineering
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• v.25 no.2
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• pp.101-106
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• 2011

In case of an emergency such as a fire on a building and there is a need to evacuate the occupant in that building, it is important to have the guidance information effectively delivered to the evacuating occupants to guide them toward a safe direction using audio sensual media. And, it is also very important to prevent the evacuating occupants getting lost or falling astray, away from the direction toward safety. The purpose of this study, in this respect, is to examine the possible application of the precedent sound effect, with which the evacuating occupants may get a sense of the direction where the announcement comes from. With such an effect, an experiment was conducted to measure the extent to which people can hear the preceding and the following sound in terms of the acoustic pressure level changes and delay time changes, with a view to make the optimal evacuation-guidance announcement or sound. The optimal evacuation guidance sound (announcement) per each of the experimental indoors environments were as follows; 1) Regarding the optimal condition for the evacuation guidance announcement sound in the space of a lecture room, the direction of the advanced sound is positively recognized when the follow-up sound has the delaying time of 10 ms~50 ms in comparison with the advanced sound or when there is no difference between the acoustic pressures of the advanced and follow-up sounds or the acoustic pressure of the advanced sound is higher than that of the follow-up sound. 2) Regarding the optimal evacuation guidance announcement sound in the space of a hall, the advanced sound is positively recognized when the follow-up sound has the delaying time of 20 ms~60 ms in comparison with the advanced sound. 3) Regarding the optimal evacuation guidance announcement sound in the space of a gymnasium, the advanced sound is positively recognized when the follow-up sound has the delaying time of 10 ms~40 ms in comparison with the advanced sound or when the sound pressure of the advanced sound has a higher level than or the same level as that of the follow-up sound.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.757-763
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• 2018

It is very difficult to achieve sufficient data rate and required quality of service due to the time-varying nature of the radio channel and various jammers such as path loss, delay, Doppler, shadowing and interference. Especially, the propagation path between the transmitting antenna and the tracking antenna mounted on the fuselage during the test and evaluation of the projectile system considered in this paper is based on the rapid movement of the projectile, the interference due to multipath fading due to the terrain, The propagation path may be blocked. In order to effectively improve the multipath fading occurring in the wireless communication system, a diversity combiner technique is required. In this paper, to derive the design and improvement schemes for the space diversity combiner technique among the diversity combiner schemes, the BER performance of maximum ratio combining (MRC) and selection combining (SC) In an adaptive SC / MRC diversity combiner that operates with MRC when it is lower than the specified threshold criterion when comparing the SNR between two signals received from the channel and operates with SC at high and combines the two received signals The BER performance of the system was compared and analyzed.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.1
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• pp.42-56
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• 2002

It is possible but not efficient to model and simulate asynchronous microprocessors with the existing HDLs(HARDware Description Languages) such as VHDL or Verilog. The reason it that the description becomes too complex. and also the simulation time becomes too long to explore the design space. Therefore it is necessary to establish a methodology and develop a tool for modeling the handshake protocol of asynchronous microprocessors very easily and simulating it very fast. Under this objective an efficient CAD(Computer Aided Design) tool SLEDS(System Level Event-Driven Simulator) was developed which can evaluate performance of a processor through modeling with a simple description an simulating with event driven engine in the system level. The ultimate goal in the tool SLEDS is to fin the optimal conditions for a system to produce high performance by balancing the delay of each module in the system. Besides SLEDS aims at verifying the design through comparing the expected results with the actual ones by performing the defined behavior.

• The KIPS Transactions:PartA
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• v.14A no.3 s.107
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• pp.173-184
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• 2007

Garbage collection in the Java virtual machine is a core function that relieves application programmers of difficulties related to memory management. In this paper, we evaluate and analyze the performance of GenGC and GenRGC, garbage collectors for embedded Java virtual machines. For performance evaluation, we employ CVM, a real embedded Java virtual machine developed by Sun Microsystems, Inc., as a platform and also use a widely-used SpecJVM98 as a set of benchmark programs. To compare the performance of GenGC and GenRGC, we first evaluate the time of garbage collection and the delay time caused by garbage collection. Second, for more detailed performance analysis of GenRGC, we evaluate the time of garbage collection and the delay time caused by garbage collection while changing the sizes of a block and a frame. Third, we analyze the size of storage space required for performing GenRGC, and show GenRGC to be suitable for embedded environment with a limited mont of memory. Since CVM is the most representative one of embedded Java virtual machines, this performance study is quite meaningful in that we can predict the performance of garbage collectors in real application environments more accurately.