• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.3C
• /
• pp.85-94
• /
• 2012

This paper described a centrifuge study in order to investigate ground-underground hollow structure interaction-induced rocking behavior in liquefied ground. Uplift of the underground hollow structures is initiated due to liquefaction in sandy grounds when the ground is exposed to a strong shaking during earthquakes because the apparent unit weight of these structures is smaller than that of the liquefied soil. In order to evaluate the dynamic behavior of the underground hollow structure and the effects of original subsoil during the uplifting, model tests were performed by changing the relative density of the original subsoil and installing an acrylic box as a trench. The results of the present study show that rocking behavior of the underground hollow structure due to shear deformation of the surrounding subsoil or lateral movement from the original subsoil contributed to large magnitude of the uplift due to strong shaking.

• Journal of the Korean GEO-environmental Society
• /
• v.11 no.12
• /
• pp.27-35
• /
• 2010

The structures built under the groundwater level are affected by the buoyancy force, which is hydrostatic pressure in the up direction. Recently, buoyancy-resistant anchor method has been applied in many cases of the construction of the important structure of large size, which is built under the groundwater level so that it takes high uplift pressure. Even if the construction cost of the method is very high, it surely increases the safety rate. However, the diagnosis of the performance of the buoyancy-resistant permanent anchor and the investigation of resistance mechanism are still insufficient. Especially, the long-term behavior of the anchor has not been studied well due to the difficulty in observation procedure. The contribution of this paper is the establishment of reasonable design methodology. We have measured anchor axial forces for 10 years after the construction, by using an automated measurement and a manual measurement by establishing a load cell in anchor head. Through the data collected from the measurements, we analyze the construction-step behavior of the anchor according to the self-weight variation of the building and the long-term behavior (i.e. movement within 10 years after the construction) of the anchor according to the passage of time.

• The Journal of Engineering Geology
• /
• v.33 no.2
• /
• pp.229-240
• /
• 2023

Instruments are installed in soft ground improvement projects to manage economic and safe construction. When analyzing data, the amount of settlement data over time can be used to understand the overall ground settlement behavior, but it is difficult to analyze the interrelatedness between measurement points. Therefore, to analyze the relative compressive settlement behavior between measurement points, the settlement amount and velocity were processed and defined as the mean settlement difference index (AS_i,j) and the slope difference index (SDI_i,j). Plotted in the mean settlement difference index - slope difference index (AS_i,j-SDI_i,j) coordinate system. As a result of the analysis of the relative compaction subsidence behavior between the measuring points, the relationship between the measuring points in the average subsidence difference index - slope difference index coordinate system moved to area 1 as the compaction was completed. By continuously plotting the movement path of the observation point in the corresponding coordinate system, the relative settlement behavior between the measurement points was analyzed, and it was possible to check whether the settlement behavior of the two measurement points was stable or unstable depending on the direction of the path.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.24 no.1
• /
• pp.280-292
• /
• 1997

The purpose of this study was to assess the sedative effect of three kinds of medication for management of the uncooperative 60 children aged from 16 months to 87 months required extensive treatment. The patients were given randomly a dose of 75mg/kg of chloral hydrate and hydroxyzine 25mg orally or 0.5mg/kg of midazolam orally or 0.3mg/kg of midazolam intranasally. All the children were restrained in a Pediwrap and were monitored with Pulse oximeter for assessing the safety of patients. According to rating scale, sleep, crying, movement, and overall behavior were checked for evaluation of the clinical sedative effect. The results were as follows: 1. In the evaluation of sleep, rating scale of chloral hydrate/hydroxyzine was superior to the other group(p<0.05). 2. In the evaluation of crying and movement at beginning of treatment, rating scale of chloral hydrate/hydroxyzine was superior to the other group(p<0.05), but during the treatment, rating scale of each group was not significantly different (p>0.05). 3. In the evaluation of overall behavior, 80% children of chloral hydrate/hydroxyzine were rated good or very good. With the oral and intranasal midazolam, 60% children were rated good or very good respectively. 4. There were no clinical signs of significant cyanosis and respiratory depression. Clinically, chloral hydrate/hydroxyzine was proved to be more effective sedation than any other sedative method. Oral and intranasal midazolam were also safe and effective sedation in young children undergoing pediatric dental procedures.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.5
• /
• pp.108-114
• /
• 2010

The injection nozzle of an electro-hydraulic injector is being opened and closed by movement of a injector's needle which is balanced by pressure at the nozzle seat and at the needle control chamber, at the opposite end of the needle. In this study, the effects of needle movement in a piezo-driven injector on unsteady cavitating flows behavior inside nozzle were investigated by cavitation numerical model based on the Eulerian-Lagrangian approach. Aimed at simulating the 3-D two-phase flow behavior, the three dimensional geometry model along the central cross-section regarding of one injection hole with real design data of a piezo-driven diesel injector has been used to simulate the cavitating flows for injection time by at fully transient simulation with cavitation model. The cavitation model incorporates many of the fundamental physical processes assumed to take place in cavitating flows. The simulations performed were both fully transient and 'pseudo' steady state, even if under steady state boundary conditions. As this research results, we found that it could analyze the effect the pressure drop to the sudden acceleration of fuel, which is due to the fastest response of needle, on the degree of cavitation existed in piezo-driven injector nozzle.

• The KIPS Transactions:PartC
• /
• v.14C no.2
• /
• pp.171-178
• /
• 2007

In mobile ad hoc networks, an application scenario requires mostly group mobility behavior in the mix of group moving nodes and individually moving nodes. The nodes of those applications tend to belong to the movement group with similar movement behavior. Group mobility is one of the good methods to improve scalability, and reduces the protocol overhead. In this paper, we propose the multicast architecture which regards nodes that have equal group mobility in the heterogeneous group mobility network as the single entity with the multiple interfaces and composes multicast tree, The logical cooperative entity-based multicast architecture accommodates the scalability, the multicast tree simplification, and the protocol overhead reduction which arc obtained from the hierarchical multicast architecture, while it maintains the nat multicast architecture for the data transmission. It also prevents the concentration of the energy consumption dispersing data forwarding load into the several ingress/egress nodes. Results obtained through simulations show that logical cooperative entity based multicast protocol with multiple interfaces offers the protocol scalability and the efficient data transmission.

• Journal of Digital Convergence
• /
• v.16 no.4
• /
• pp.371-378
• /
• 2018

The purpose of this study is to investigate the effect of family relations on facility adaptation of the elderly. In January and February of 2018, a questionnaire survey was conducted on 5 ~ 6 elderly residents of each long-term care facility, and finally 353 data were used for analysis. The main results of the study were as follows: First, the adaptation level of the elderly was high. As for 'maladjustment of group behavior' and 'movement shock', the level of maladjustment is low as 2 points, and adaptation dimension such as 'accept of new residence' and 'making friend' is above the middle level. Second, the influence of family variables was more influential than the demographic characteristics of the elderly and the influence of the facility-related variables. Among them, the closeness with family is the most influential. Therefore, it is suggested that the elderly need active support and efforts to maintain the intimacy with the family from the entrance to the facility and the time after the entrance.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.4
• /
• pp.811-824
• /
• 1998

The purpose of this study was to compare the clinical sedation effect of chloral hydrate and hydroxyzine combination, midazolam, triazolam when young children were sedated for dental treatment. The uncooperative 22 children aged, 25 to 52 months of age(ASA class I) and weighting between 11 and 17kg, participated in the study. Each patient was assigned randomly to receive chloral hydrate(50mg/kg) and hydroxyzine HCl(25mg), midazolam(0.5mg/kg), and triazolam(0.25mg) oral administration : alternative regimens were administered at next appointment. According to rating scale, sleep, crying, movement, and overall behavior response were checked for evaluation of the clinical sedation effect. Pulse rate and oxygen saturation were also measured for monitoring the patients during treatment period by pulse oximeter. The results were as follows: 1. In the evaluation of sedation effect, 90.9% in chloral hydrate and hydroxyzine combination and midazolam, and 77.3% in triazolam were rated "good" or "very good". 2. Sleep was demonstrated to be statistically significant increase in chloral hydrate and hydroxyzine combination group. Despite the fact that chloral hydrate and hydroxyzine group was in a deeper state of sleep, all the children were easily aroused. 3. There were no statistically significance among the three regimens with regard to cry ing, movement, overall behavior. 4. The adverse side effect was vomiting in one patient of chloral hydrate and hydroxyzine combination. There were no clinical sign of respiratory depression.

• International Journal of Precision Engineering and Manufacturing
• /
• v.6 no.1
• /
• pp.51-58
• /
• 2005

The development of the high-efficiency machine-tools equipment and new cutting tool materials with high hardness, heat- and wear-resistance has opened the way to application of high-speed cutting process. The basic argument of using of high-speed cutting processes is the reduction of time and the respective increase of machining productivity. In this sense, the spindle units may be regarded as one of the most important units, directly affecting many parameters of high-speed machining efficiency. One of the possible types of spindle units for high-speed cutting is the air-bearing type. In this paper, we propose the mathematical model of the dynamic behavior of the air-bearing spindle. To provide the high-level of speed capacity and spindle rotation accuracy we need the adequate model of "spindle-bearings" system. This model should consider characteristics of the interactions between system components and environment. To find the working characteristics of spindle unit we should derive the equations of spindle axis movement under the affecting factors, and solve these equations together with equations which describe the behavior of lubricant layer in bearing (bearing stiffness equations). In this paper, the three influence coefficients are introduced, which describe the center of spindle mass displacement, angle of shaft rotation around the axes under the unit force application and that under the unit torque application. These coefficients are operated in the system of differential equations, which describes the spindle axis spatial movement. This system is solved by Runge-Kutta method. Obtained trajectories and amplitude-frequency characteristics were then compared to experimental ones. The analysis shows good agreement between theoretical and experimental results, which confirms that the proposed model of air-bearing spindle is correctis correct

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1643-1646
• /
• 2003

Drawing is a mechanical operation that attenuates thick material to an appropriate thickness for the next processing or end usage. When the input material has the form of a bundle or bundles made of very thin and long shaped wire or fibers, this attenuation operation is called "bundle drawing" or "drafting" Drafting is being used widely in manufacturing staple yarns. which is indispensable for the textile industry. However, the bundle processed by this operation undertake more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. Since long there have been many researches tying to find out factors affecting the irregularity of linear desity, to obtain optimal drafting conditions, to develop efficient measuring and analysis methods of linear density of bundle, etc., but there exists yet no fundamental equation describing the dynamic behavior of the flowing bundle during processing. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical lows representing physical variables, i.e. linear density and velocity as the dynamic state of bundle. The conservation of mass and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.