• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.2
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• pp.4116-4120
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• 1976

With the use of many rivers increased nearly to the capacity, the need for information concerning daily quantities of water and the total annual or seasonal runoff has became increased. A systematic record of the flow of a river is commonly made in terms of the mean daily discharge Since. a single observation of stage is converted into discharge by means of rating curve, it is essential that the stage discharge relations shall be accurately established. All rating curves have the looping effect due chiefly to channel storage and variation in surface slope. Loop rating curves are most characteristic on streams with somewhat flatter gradients and more constricted channels. The great majority of gauge readings are taken by unskilled observers once a day without any indication of whether the stage is rising or falling. Therefore, normal rating curves shall show one discharge for one gauge height, regardless of falling or rising stage. The above reasons call for the correction of the discharge measurements taken on either side of flood waves to the theoretical steady-state condition. The correction of the discharge measurement is to consider channel storage and variation in surface slope. (1) Channel storage As the surface elevation of a river rises, water is temporarily stored in the river channel. There fore, the actual discharge at the control section can be attained by substracting the rate of change of storage from the measured discharge. (2) Variation in surface slope From the Manning equation, the steady state discharge Q in a channel of given roughness and cross-section, is given as {{{{Q PROPTO SQRT { 1} }}}} When the slope is not equal, the actual discharge will be {{{{ { Q}_{r CDOT f } PROPTO SQRT { 1 +- TRIANGLE I} CDOT TRIANGLE I }}}} may be expressed in the form of {{{{ TRIANGLE I= { dh/dt} over {c } }}}} and the celerity is approximately equal to 1.3 times the mean watrr velocity. Therefore, The steady-state discharge can be estimated from the following equation. {{{{Q= { { Q}_{r CDOT f } } over { SQRT { (1 +- { A CDOT dh/dt} over {1.3 { Q}_{r CDOT f }I } )} } }}}} If a sufficient number of observations are available, an alternative procedure can be applied. A rating curve may be drawn as a median line through the uncorrected values. The values of {{{{ { 1} over {cI } }}}} can be yielded from the measured quantities of Qr$.$f and dh/dt by use of Eq. (7) and (8). From the 1/cI v. stage relationship, new vlues of 1/cI are obtained and inserted in Eq. (7) and (8) to yield the steady-state discharge Q. The new values of Q are then plotted against stage as the corrected steadystate curve.

• The Korean Journal of Ecology
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• v.25 no.2
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• pp.93-100
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• 2002

In order to analyze the life cycle of A. artemisiifolia var. elation dormancy and some environmental factors inducing germination of the seeds were examined. The results were as follows : Dormancy of fertile seeds was broken in part within a month after seed collection in case of adequate moisture and alternating temperature was also effective in breaking dormancy. The temperature range, which allow germination was 12℃ ∼ 32℃. Optimum temperature for germination was 24℃. The seed of A. artemisiifolia var. elatior was light-independent. The difference of storage period appeared to have no particular effect on the viability of seeds at any time during the 9-month storage period. In the increasing temperature(IT) regime, A artemisiifolia var. elatior seeds started to germinate at 16℃, showing the higher temperature the greater germination rate, the final germination percentage was 99.34%. On the other hand, in the decresing temperature(DT) regime, seeds began to germinate at 20℃ with the 1.34% germination. An induced dormancy occurred at 12℃ making the 5.34% fecal germination in the DT regime. Low temperature was more effective to break dormancy than higher temperature Seeds of A. artemisiifolia var. elatior seems to be germinated in mid to late autumn or germination delayed until following spring. The above results suggest these variation of germination response in diverse environmental factors seems to be a physiological strategy to maintain their existence and to reproduce in the extreme thermal variation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.104-108
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• 2006

Effect of gamma irradiation on the softening of dried fernbrake at different moist-heating conditions was investigated. Dried fernbrake packaged in controlled atmosphere $(CO_2\;25\%,\;N_2\;75\%)$ was irradiated up to 7 kGy with $\gamma-ray$. Hardness of dried fernbrake was significantly decreased at the irradiation dose of above 5 kGy. Hardness of cooked fernbrake was significantly decreased with increasing irradiation dose level as well as heating temperature and time. $DT_{50}$ value (The heating time required to reach the $50\%$ reduction of hardness) for irradiated fernbrake was shortened according to dose level as well as heating temperature and heating time: $DT_{50}$ value of control: 23 min, 5 or 7 kGy: $2.2\~5.0$ min at $60^{\circ}C$. Also, the activation energy for softening of irradiated fernbrake ($1.85\~1.88$ kcal/mole for $5\~7kGy$) decreased compared to control (4.30 kcal/mole). Moisture content, swelling and rehydration rate of gamma irradiated fernbrake during moist heating increased according to the irradiation doses. Sensory results showed that scores of off-flavor and odor in irradiated fernbrake upto 7 kGy were not significantly different from control. Based on these results, gamma irradiation was effective for the reduction of cooking time and the activation energy for softening of dried fernbrake with increasing dose levels.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.211-215
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• 2004

Temperature-fecundity of the melon aphid, Aphis gossypii Glover, was studied at constant temperatures ranging from 15 to $32.5^{\circ}C$ under $60-70\%$ RH and a photoperiod of 16 : 8 (L : D) A life table parameters were constructed using the results. The longevity of A. gossypii gradually increased with decreasing temperature below $27.5^{\circ}C$. Also fecundity increased with decreasing temperature and the highest fecundity was 61.8 nymphs per female at $17.5^{\circ}C$. However. daily fecundity increased with increasing temperatures up to $22.5^{\circ}C$ showing 5.9 nymphs per day and thereafter decreased. Longevity and fecundity of the adult in the greenhouse with an average temperature of $21^{\circ}C$ and $65.6\%$ RH, were 20.0 days and 59.6, respectively, which were longer and higher than those in the growth chamber with similar conditions. net reproductive rate (Ro) was 54.9 at $17.5^{\circ}C$ while intrinsic rate of increase ($r_m$) and finite rate of increase ($\lambda$) were the highest 0.5 and 1.6 at $30^{\circ}C$, respectively. doubling time (DT) and mean generation time (T) were the shortest 1.4 and 6.8 at $30^{\circ}C$ indicating that optimal temperature for the development is $30^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.398-402
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• 1989

Moisture sorption and cooking properties of two varieties of Korean soybean(Jangyup and Whangkeum) were studied. When soybean was stored under the various relative humidities (RH) of 33-86% at 16'E for 125hours, its sorption behaviors were divided into two : desorption at the RHs of 33 and 44% and adsorption at the RHs of above 55%. The sorption rate was decreased rapidly during storage. In comparisons with only storage humidities, the sample stored at higher RH held the higher sorption rate. The relationships between storage time and sorption rate were applied well to the equation, log dw/dt= b log t+ log a, where w is the moisture content(%, db), t is time(hour) and a and b are the parameters which were calculated from the experimental data. The calculated moisture contents from the equation agreed well with the measured moisture contents. On the other hand, the cooking degrees of soybean which was steamed in an autoclave at $106-121^{\circ}C$ were compared by the maximum cutting forces. The cooking time to attain the same degree of cooking decreased logarithmically as the cooking temperature increased. The z-values which were calculated from the time-temperature combinations that gave the same degree of cooking for Jangyup and Whangkeum were $13.3^{\circ}C$ and $12.8^{\circ}C$ respectively.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.213-217
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• 2005

Adult development and fecundity of the green peach aphid, Myzus persicae $S\H{u}lzer$, were studied at $15{\sim}32.5^{\circ}C$ with $60{\sim}70%$ RH under 16L:8D and the results were put together to build a life table. The longevity shortened as temperatures rose at and below $25^{\circ}C$ whereas it remained relatively constant at $27.5^{\circ}C$. Total fecundity was not significantly different at all temperatures except at $30^{\circ}C$. Daily fecundity gradually increased from $15\;to\;22.5^{\circ}C$. It was 5.1 at $25^{\circ}C$ and as temperatures either went down or up, it decreased to 2.8 at both $15^{\circ}C\;and\;30^{\circ}C$. Fecundity model built from total fecundity at various temperatures suggests that $18.3^{\circ}C$ was the optimum temperature for the maximum progeny of 51. Net reproduction rate RO was highest of 36.5 at $27.5^{\circ}C$. The intrinsic rate of increase per day $r_m$ and the finite rate of increase per day $\lambda$ were highest of 0.4 and 1.6, respectively and the doubling time Dt was shortest of 1.6. Constructed life table suggests that the optimum temperature for adult development for the green peach aphid was $27.5^{\circ}C$ at which the mean generation time was 8.1.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.1
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• pp.9-16
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• 2023

Robots are expected to expand their scope of application to the military field and take on important missions such as surveillance and enemy detection in the coming future warfare. Swarm robots can perform tasks that are difficult or time-consuming for a single robot to be performed more efficiently due to the advantage of having multiple robots. Swarm robots require mutual recognition and collaboration. So they send and receive vast amounts of data, making it increasingly difficult to verify SW. Hardware-in-the-loop simulation used to increase the reliability of mission verification enables SW verification of complex swarm robots, but the amount of verification data exchanged between the HILS device and the simulator increases exponentially according to the number of systems to be verified. So communication overload may occur. In this paper, we propose a digital twin-based communication optimization technique to solve the communication overload problem that occurs in mission verification of swarm robots. Under the proposed Digital Twin based Multi HILS Framework, Network DT can efficiently allocate network resources to each robot according to the mission scenario through the Network Controller algorithm, and can satisfy all sensor generation rates required by individual robots participating in the group. In addition, as a result of an experiment on packet loss rate, it was possible to reduce the packet loss rate from 15.7% to 0.2%.

• Journal of Korean society of Dental Hygiene
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• v.13 no.2
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• pp.297-303
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• 2013

Objectives : The purpose of this study was to evaluate the oral health status of the disabled people in Ulsan. Methods : Two dentists taken a calibration training for national oral health survey examined the Oral health status on 110 disabled people in Ulsan, in 2009. The surveyed disabled people, 6 to 19 years old, have been supplied with the oral health care services by dentists, oral hygienists and volunteers at dental clinics of schools and a dental clinic supported from Ulsan Metropolitan City Nam-Gu Health Center since 1997. The obtained data from these surveys were analyzed with the SPSS statistical package. Results : Among subjects aged 12-14 years, DMF rate was 38.2%; Active D rate, 17.6%; DMFT index, 1.15; DT rate, 33.33%; MT rate, 0.00%; FT rate, 66.67%. Oral heath status of disabled people in Ulsan were evaluated to be a similar level to the Ulsan non-disabled citizens from 2010 Korean National Survey. Conclusions : The oral health care programs for disabled people using voluntary dentists, oral hygienists and other workers in Ulsan are evaluated to be effective for the disabled people.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.342-348
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• 2014

This study was carried out an elementary school located in B-myeon and K-myeon of Gimje. One school (test group) with a school oral health care office and three schools (control group) without school oral health care offices were selected as sample schools. The dental caries prevention effects were compared between third to sixth graders who received benefits of the school continued oral health management program of K health office in Gimje, and first and second graders who did not receive the benefits due to the suspension of the program. The decayed, missing, and filled (DMF) rate, that received the benefits of the program, the test group was 58.9% and the control group was 76.1%, showing significant difference (p<0.05). For the DMF teeth (DMFT) rate, the who received benefits from the program, the test group was 41.1% and the control group was 64.2%, showing significant difference (p<0.01). For the DMFT index, the third to sixth graders that received benefits of the program, the test group was 1.73 and the control group was 3.66 showing significant difference (p<0.001). For the decayed teeth (DT) index, it was 0.72 for the test group and 1.96 for the control group showing significant difference (p<0.001). For the filled teeth index, the test group was 0.63 for the test group and 0.99 for the control group showing significant difference (p<0.05). For the DT rate, the total test group was 57.23% and 64.16% for the control group. For who received benefits from the program, the DT rate was 54.81% for the test group and 60.98% for the control group. The effects of the student continued oral health management program carried out by the oral health office can be confirmed. It is judged that efforts for continuous maintenance and promotion will be necessary to improve the oral health of students.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.77-80
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• 2003

Switching Mode Power Supply(SMPS) is widely used in many industrial fields. Power factor improvement and harmonic reduction technique are very important in SMPS. In this paper, we propose the circuit applied Flying Capacitor Snubber for improving power factor of boost converter on fast switching state. Snubber circuit consists of a inductor, two diodes and a capacitor. The losses of switching are reduced by inserting a snubber inductor in the series path of the boost switch and the rectifier diode to control the di/dt rate of the rectifier during it's turn-off. Prior to actual experiment, the circuit analysis Is implemented by PSPICE simulation.