• Journal of Advanced Navigation Technology
• /
• v.4 no.1
• /
• pp.50-66
• /
• 2000

For a long time target maneuvers in tracking problem have been a difficult task to handle. Once a maneuvering such as abrupt change in target accelerations occur, the tracking fiter no longer yields a reasonable estimate of the target position. In order to resolve this cumbersome maneuvering problem. Advanced methods have here proposed : Colored noise, IE(Input Estimation), VD(Variable Dimension), IMM(Interaction Multiple Model), Jump-type processes and jerk model, etc. In this paper, tracking performance of the jerk model is analyzed. Jerk model in which the derivative of target acceleration is included as a state recently attracted considerable attraction. Firstly 3-dimensional Kalman filter is described on the basis of jerk model. Then using this filter, Monte-Carlo simulations are carried out and the filter formance with respect to the variation of jerk time-constant is analyzed. Especially, since jerk model's transient performance is expected to be poor, the performance of analysis of transient response of the model is included too.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.3
• /
• pp.253-261
• /
• 2000

Head-out water immersion induces marked increase in the cardiac stroke volume. The present study was undertaken to characterize the stroke volume change by analyzing the aortic blood flow and left ventricular systolic time intervals. Ten men rested on a siting position in the air and in the water at $34.5^{circ}C$ for 30 min each. Their stroke volume, heart rate, ventricular systolic time intervals, and aortic blood flow indices were assessed by impedance cardiography. During immersion, the stroke volume increased 56%, with a slight (4%) decrease in heart rate, thus cardiac output increased ${\sim}50%.$ The slight increase in R-R interval was due to an equivalent increase in the systolic and diastolic time intervals. The ventricular ejection time was 20% increased, and this was mainly due to a decrease in pre-ejection period (28%). The mean arterial pressure increased 5 mmHg, indicating that the cardiac afterload was slightly elevated by immersion. The left ventricular end-diastolic volume index increased 24%, indicating that the cardiac preload was markedly elevated during immersion. The mean velocity and the indices of peak velocity and peak acceleration of aortic blood flow were all increased by ${\sim}30%,$ indicating that the left ventricular contractile force was enhanced by immersion. These results suggest that the increase in stroke volume during immersion is characterized by an increase in ventricular ejection time and aortic blood flow velocity, which may be primarily attributed to the increased cardiac preload and the muscle length-dependent increase in myocardial contractile force.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.3
• /
• pp.169-175
• /
• 2000

To learn the developmental changes in intrinsic electrophysiological properties of the second order taste neurons, whole cell recordings from the developing nucleus of the solitary tract neurons were done in brainstem slices of postnatal rats. Rats aged from postnatal 0 to 21 days (P0-P21) were used, being divided into 3 age groups: postnatal first week (P0-P7 days), second week (P8-P14 days), and third week (P15-P21 days). Slices containing gustatory NTS were cut horizontally in the thickness of $300\;{\mu}m.$ Whole cell recordings were obtained from neurons in response to a series of hyperpolarizing and depolarizing current pulses. The intrinsic electrophysiological properties of the rostral NTS (rNTS) neurons were compared among the age groups. Depolarizing current pulses evoked a train of action potentials in all neurons of all age groups. The resting membrane potential and input resistance of the neurons did not show any significant differences during the postnatal 3 weeks. The time constant, however, decreased during the development. Duration of action potential measured at half maximum amplitude was longer in younger age groups. Both the maximum rate of rise and the maximum rate of fall in the action potential increased during the first 3 weeks postnatal. Electrophysiologically more than half neurons were type III. In summary, it is suggested that developmental changes in electrophysiological properties in rNTS occur during the first three weeks in rats.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.3
• /
• pp.227-234
• /
• 2000

Many reports suggest that neurotensin (NT) in the gastrointestinal tract may play a possible role as a neurotransmitter, a circulating hormone, or a modulator of motor activity. NT exerts various actions in the intestine; it produces contractile and relaxant responses in intestinal smooth muscle. This study was designed to investigate the effect of NT on motility of antral circular muscle strips in guinea-pig stomach. To assess the role of $Ca^{2+}$ influx in underlying mechanism, slow waves were simultaneously recorded with spontaneous contractions using conventional intracellular microelectrode technique. At the concentration of $10^{-7}$ M, where NT showed maximum response, NT enhanced the magnitude $(863{\pm}198%,\;mean\;SEM,\;n=13)$ and the frequency $(154{\pm}10.3%,\;n=11)$ of spontaneous contractions. NT evoked a slight hyperpolarization of membrane potential, tall and steep slow waves with abortive spikes $(278{\pm}50%,\;n=4).$ These effects were not affected by atropine $(2\;{\mu}M),$ guanethidine $(2\;{\mu}M)$ and tetrodotoxin (0.2μM). NT-induced contractile responses were abolished in $Ca^{2+}-free$ solution and reduced greatly to near abolition by $10\;{\mu}M$ of verapamil or 0.2 mM of $CdCl_2.$ Verapamil attenuated the effects of NT on frequency and amplitude of the slow waves. Taken together, these results indicate that NT enhances contractility in guinea-pig gastric antral circular muscle and $Ca^{2+}$ influx through the voltage-operated $Ca^{2+}$ channel appears to play an important role in the NT-induced contractile mechanism.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.5
• /
• pp.507-513
• /
• 2000

Objective : The purpose of this study is to evaluate the vitality of the teeth in and adjacent to the mandibular fracture line according to variable conditions of fracture and to establish the protocol of treatment of fracture line teeth. Materials and Methods : The vitality of 97 teeth in fracture line and 104 teeth adjacent to fracture line of 52 patients were invested preoperatively. Of these, 66 teeth in fracture line and 72 teeth adjacent to fracture line were monitored at least 6 months after operation. An electric pulp tester was used to measure pulpal response. The relationships between the vitality of teeth in variable time(preoperation, immediate post-operation; within 1 week after operation, and 6 months after operation) and variable conditions of fracture(horizontal, vertical gap of fracture line, the number of fracture line)were evaluated statistically. Result : The vitality of fracture line teeth in the 6 months after operation statistically differed by the vertical gap of fracture line and the number of fracture line. The vitality of fracture line adjacent teeth in the immediate post-operation only statistically differed by the vertical gap of fracture line. There were statistically differences between preoperative EPT value and vitality of fracture line teeth on 6 months after operation. There were 5 cases of complications including periapical and periodontal abscess. Of these, only one tooth was extracted and the others were well treated with endodontic treatment and subgingival curettage. Conclusion : It is recommended to retain teeth and to monitor the vitality of teeth in and adjacent to fracture line, unless there is an absolute indication for extraction.

• Asian Journal for Public Opinion Research
• /
• v.4 no.4
• /
• pp.208-245
• /
• 2017

Background: Attitudes toward breastfeeding in public are one potential barrier to optimal breastfeeding rates and durations. Method: Questions about breastfeeding experience and attitudes toward breastfeeding in public were asked in face-to-face interviews as part of the Korean Academic Multimode Open Survey (KAMOS), May-July, 2017. The response rate was 65.8% (2000 respondents nationwide). Results: A majority of Koreans disagreed (1 or 2 on a 4-point scale) with the statement "Women should not breastfeed their child in open, public places" (53.9%) and agreed (3 or 4 on the 4-part Likert scale) with the statements "I do not feel uncomfortable seeing women breastfeed their child in open, public places" (64.0%) and "Breastfeeding a baby, instead of letting the baby cry, in public places is better for other people" (71.8%). However, despite these generally positive attitudes, the majority also said that they would not breastfeed in public (57.4% of women) or, in the case of men, would not want a close female relative to do so (63.8% of men). Breastfeeding in public was positively correlated with the duration of breastfeeding. People were more positive about breastfeeding in public if they: were parents; did not use formula and breastfeeding a similar amount; had children who had been breastfed in public; were older; were Buddhists rather than Christians. An attempt was made to compare attitudes toward breastfeeding in public and breastfeeding durations internationally, but was inconclusive due to not perfectly comparable data. Conclusion: Our results may be useful in planning public health campaigns in South Korea or future attempts at international comparisons to better understand and address the effect of public opinion regarding breastfeeding in public on breastfeeding rates and durations.

• Journal of Environmental Health Sciences
• /
• v.29 no.4
• /
• pp.27-34
• /
• 2003

Bisphenol A is used in the manufacture of epoxy, polycarbonate, and corrosion-resistant unsaturated polyester-styrene resins required for food packaging materials in industrial processing. Some reports indicated the possibility of harmful effects on rats. In this study was used a method for the determination of bisphenol A in blood according to the OSHA High Performance Liquid Chromatography (HPLC) guideline. The method involved blood extraction using methylene chloride. And it was evaluated developmental and teratogenic effects in pregnant rats and second generation. The results obtained were as follows. There was a significant increase in the body weights and treated groups F1 female in liver, spleen, kidney, but according to dose-response. F1 female rat's relative body weight and absolute body weight are not different. There was a significant increase liver, spleen, kidney organ weight and reproductive organ weight epididymis, prostate gland in F1 male rats. There was a proestrous in pregnant rat, group 200 $\mu\textrm{g}$/kg, 2000 $\mu\textrm{g}$/kg, 20,000 $\mu\textrm{g}$/kg. The effect on rat treated with bisphenol A decrease organ weight and reproductive organ weight. Identification and quantitation were performed with using HPLC C18 column and using at retention time 5.5 min. The results of the detection of bisphenol A were at 20,000 $\mu\textrm{g}$/kg in average 1 $\mu\textrm{g}$/ml, 200 $\mu\textrm{g}$/kg average in 0.9 $\mu\textrm{g}$/ml blood samples. From those results, it could be concluded that the effects of pregnant rat and second generation(F1) by bisphenol A treatment during lactational period were estrogenic and bisphenol A was remained in serum at low level.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.6 no.1
• /
• pp.147-159
• /
• 2000

The purpose of this study was to investigate the performance of clinical competency in nursing graduates and clinical nurses. The total of 234 subjects returned the questionnaire with 95% of response rates. The subjects of the study constituted of 195 nursing graduates and 39 clinical nurses. Self report questionnaires were used to measure the clinical competence of nursing graduates and clinical nurses. This instrument had four dimensions of competency : client and health need, nursing process, professional role, and nursing interventions. The data were analyzed by utilizing SPSSWIN and the results were as follows. 1) The mean score of the nursing intervention dimension was the most with 3.82 compared to professional role dimension(3.06), nursing process(3.03), client and health need dimension(2.94) in nursing graduates. 2) The mean score of the nursing intervention dimension was the most with 3.04 compared to client and health need dimension(2.82), professional role dimension(2.81), nursing process(2.77) in clinical nurses. And all of these dimensions' scores were lower than the nursing graduates' scores. 3) The mean scores of nursing process (t=3.76, p<.001) and professional role dimensions(t=3.53, p<.001) in nursing graduates were significantly higher than clinical nurses' scores. Our suggestions based on the results of this study is : 1. It is recommended to repeat the same designed study in large sample of clinical nurses for further study.

• Physical Therapy Korea
• /
• v.7 no.1
• /
• pp.55-63
• /
• 2000

Physical therapists have been using balance and weight shifting training to induce improvements in standing and walking. This study compared the effects of kinetic feedback frequency and concurrent kinetic feedback on the performance and learning of a weight shifting skill in young, nondisabled adults. Sixteen young adults without known impairment of the neuromusculoskeletal system volunteered for the study. Subjects in each of three kinetic feedback groups performed a weight shifting task in an attempt to minimize error between their effort and a center of pressure (COP) template for a 12 second period. Feedback was provided: 1) concurrently (concurrent feedback), 2) after each trial (100% feedback), 3) after every other trial (50% feedback). Immediate and delayed (24 hour) retention tests were performed without feedback. During acquisition phase, the concurrent feedback group exhibited less error than either of the post response feedback group. For the immediate retention test, the 50% feedback group exhibited less error than did the 100% feedback and concurrent feedback. During the delayed retention, 50% feedback group displayed less error than did the other groups. But no significant differences were found between groups. These results suggest that practice with concurrent feedback is beneficial for the immediate performance, but not for the learning of this weight shifting skill. Lower frequency of feedback resulted in more permanent changes in the subject's ability to complete the task.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.187-190
• /
• 2000

Effects of gamma ionizing radiation on recombinant Escherichia coli cells containing stress promoters, recA, fabA, grpE, or katG, fused to luxCDABE originated from Vibrio fischeri were characterized by monitoring transcriptional responses reflected by bioluminescent output. Quantification of gamma-ray intensity may be possible using the recA and fabA promoter fusion since a linear enhancement of bioluminescence emission with increasing gamma-ray intensity was observed. Other strains sensitive to either oxidative stress (DPD2511, katG::luxCDABE) or protein-damaging stress (TV1061, grpE::luxCDABE) were also irradiated by gamma-rays, and resulted in no noticeable bioluminescent output while DPD2794 with recA promoter and DPD2540 with fabA promoter irradiated by the same intensities of gamma-rays gave a significant bioluminescent output. This indicates that the main stresses in the recombinant bacteria caused by ionizing radiation are DNA and membrane-damage, not protein- or oxidative-damage. In addition, in this study, to investigate the relationship between the radiation dose rate and bacterial responses, two recombinant Escherichia coli strains, DPD2794 and GC2, containing lac promoter fused to luxCDABE originating from Photorhapdus luminescences, were used for detecting DNA damage and cellular toxicity under various radiation dose rates. Throughout this study, it was found that these bacteria showed quantitative stress responses to DNA damage and general toxicity caused by gamma rays, depending on the radiation dose rates, indicating that the bacterial stress responses and general toxicity were seriously influenced according to radiation dose rates.