• Electronics and Telecommunications Trends
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• v.37 no.4
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• pp.36-45
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• 2022

As the interest in achieving an intelligent society grows with the fourth industrial revolution's development, information and communications technologies technologies like artificial intelligence (AI), Internet of Things, virtual reality, information security, and blockchain technology are being actively employed in different fields for achieving an intelligent society. With these modifications, the information security paradigm in industrial and public institutions, like personal sensitive data, is quickly changing, and it is exposed to different cyber threats and breaches. Furthermore, as the number of cyber threats and breaches grows, so does the need for rapid detection and response. This demand can be satisfied by establishing cyber training programs and fostering experts that can improve cyber security abilities. In this study, we explored the domestic and international technology trends in cyber security education and training facilities for developing experts in information security. Additionally, the AI technology application in the cyber training ground, which can be established to respond to and deter cyber threats that are becoming more intelligent, was examined.

• Magazine of the Korea Concrete Institute
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• v.11 no.1
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• pp.109-118
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• 1999

Seismic design code has been performed since 1988 in Korea, so it has not been applied to low-rise reinforced concrete buildings which had been built before 1988. Those building have been designed only for gravity loads based on non-seismic code, Therefore, even minor earthquake occurred, those buildings might have serious damages. In this paper, to investigate the behavior of low-rise reinforced concrete moment resisting frame which had been built in according to the building code of Korea that had been published before 1988, two type of 1/2 scaled exterior beam-column subassemblies which have non-seismic detailing based on the building code of Korea were constructed and tested with reversed cycling loading under the displacement control method. The special features of joint with non-seismic detailing is that there is no transverse reinforcement in the joint. In tests, cracks pattern, strength degradation, loss of stiffness, energy dissipation and the slippage of beam and column bars were investigated. Cracks did not occurred in the joint even seismic loading of 0.12g which is considered as peak ground acceleration in Korea was applied. And increasing seismic loading above 0.12g shear crack happened in the joint which have not transverse beam.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.1
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• pp.2535-2548
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• 1972

Instead of fertilizing the lands they moved to find other fertile lands and lived a feudal life agriculture and various machincs played a main role in the land reclamation. The best method of land clearing, the time and capacity in the operation and the effect of growing crops should systematically analized prior to the time of 3rd Five-year Economic Development(1972-1976) in order to cultivate 210,000ha of wasteland or the modernization of our country. The present study was investigated to find out a new working-system of mechanical land clearing and development of fertile soil. The results are as follows: 1) The first stage of productive power increases when weeds were mixed soil in the land clearing work in order to supply organic materials and to make soil swollen instead of burning or just removing. 2) The equipments such as bulldozers, harrows, power tillers and so on should be prepared in order to do a systematic work in the land clearing. 3) The work of pulling-up roots is dependent upon the forms of roots spreading under the ground. The work of the pulling-up of the straight roots was most difficult. But before the roots are pulling-up we do not know the forms of roots. 4) The cutting of soil from upside to under side land clearing method (II) Spent 6 hr 7 min 43 sec per 1 Danbo in doing land clearing and control method spent 4 hr 52 min 30 sec per 1 Danbo in doing land cearing. No significant difference could be found between II treatment type and I treatment type. 5) The volume of soil carried by bulldozer $270.38m^3$ per 1 Danbo in I type and in II type, $368.58m^3$ per 1 Danbo or about 36% increased in II type then in I type. But that is not a significant difference when considering the whole productive power of soil. 6) The land clearing of terrace by bulldozers cannot escape making the embankment slope of about $45^{\circ}$, and 25.3% should be decreased in the area. It is recommended to make use of the embankment slope by planting grass for cows. 7) The time of retary tilling increased 2.3 times or 1 hr 42 min 22 sec per 1 Danbo compared to the timesrequired in the harrowing. Because it mixed the Organic matter on ground and the harrowing of subsoil. 8) The havest of pasture growing on the land reclamation in natural slope is as follows. (a) The none fertilizers with reclaimed block of productivity decresed 1/10 than that of the farmland. Therefore the none fer tilizing in the cultivated pasture is unprofitable. (b) The havest of the manured IV treatment block was the best not only in the kinds of fertilizers but also in the kinds of pasture grass.

• Magazine of the Korea Concrete Institute
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• v.5 no.4
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• pp.123-134
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• 1993

A rapid progress has been made over last decade in the state-of-the-art earthquake structura1 engineering towards a better understanding of both the earthqauke ground motion and structural response. These efforts seek to ensure that there will be no serious injury or loss of life in the event of earthquake, and that structures can be built at minimum cost. The design of structures in general, concrete structures in particular, to resist strong ground input motions is not a simple matter, and analytical models for such structures must be developed from a design perspective that accounts for the complexities of the structural responses. The primary obj ective of earthquake structural engineering research is to ensure the safety of structures by understanding and improving a design methodology. Ideally, this would require the development of an analytical model related to a design methodology that ensures a ductile performance. For the accurate assessment of the adequacy of analytically developed model, experiments conducted to study the inplane inelastic cyclic behavior of structures should verify the analytical approach. The fundamental goal of this paper is to present and demonstrate experimentally verified analytical methods that provide the adequate degree of safety and confidience in the behavior of reinforced concrete structural components. This study further attempts to extend the developed modeling techruque for use by practicing structural engineers for both the analysis and design.Plication of the relaxed diaphragm through left thoracotomy was done and result was excellent as seen on Fig. 5. Cause of eventration of the left hemidiaphragm was due to paralysis of the left phrenic nerve which was tested during thoracotomy.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.223-231
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• 1998

Existing cast in place piles made by grouting cement mortar have many problems that cracks by autogeneous and drying shrinkage bring about the deterioration of force for piles, segregations by the submersion of ground water occur and also, high cement contents lead to rise the manufacturing cost. Therefore, this study is intended to investigate the mechanical properties of high performance mortar, incorporating expansive additives and fly ash. for cast in place piles. According to the experimental results, as the contents of expansive additives increase in mortar mixture, fluidity decrease and air contents shows inverse tendency. Setting time is delayed. Although compressive strength at 7days shows a decline tendency. compressive strength at 28days and 91days increase slightly with 5% of expansive additives. As fly ash increase in mortar mixture, high fluidity is shown, air contents increase and setting time is delayed at fresh state, and additives are, the larger length change is, whereas shrinkage decrease with the increase of fly ash.

• Journal of the Korean Professional Engineers Association
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• v.25 no.4
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• pp.102-108
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• 1992

This study was carried to find out the soil characteristics of landslide site and to develope landslide prediction method by seismic refraction prospecting. For these aims, landslide condition and travel time were investigated at 68 Landslide sites over the country during 1990 to 1991. The results were as follows. 1. The surface of rupture was included mainly in C layer. Its Hardness was less than 3kg / $\textrm{cm}^2$ at the upper pare of landslide. 2. When the profile line length was 20m, the range of travel time was 40 to 90 msec. The travel time did not differ between bedrocks. 3. Refraction distance ranged from 1 to 7m and mean of that was 2.5m. Travel time was increased according to receiving distance without large variance in the refraction distance but that was appeared large variance out of the refraction distance on slope that has shallow soil depth and discontinuous ground surface. Therefore, the spread distance must be shorten to 10-l5m. 4. The seismic velocity at the first layer(layer of rupture) was less than 500m1sec by degree of weathering and the velocity at the second layer decreased in order of Granite> Granitic gneiss >Sedimentary rock. 5. The first layer observed by seismic refraction was contained C layer that has parent material and weathered rocks of hardness 10-20kg/$\textrm{cm}^2$. 6. Among the range of seismic velocity was less than 200m/sec in 63% of the total plots, 200-300m/sec in 34% and 300-500m /sec in 3%. 7. There was a proportional relationship between seismic prospecting soil depth and executive soil depth, and seismic propection soil depth was about 10 to 20cm deeper than the order.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.1
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• pp.116-127
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• 1996

This paper dealt with FEM analysis of foundation improved with pack drain. The theory on pack drain was scrutinized and observed values in the field were compared with numerical results. Work site of Kwangyang container pier was selected as a ease study in which measurement of settlement and pore water pressure was accurately carried out. Biot's consolidation equation was selected as governing One, coupled with modified Camclay model as constitutive one. Christian and Boehmer's numerical technique was adopted. Behavior of foundation with pack drain is not simple but very complicated. Discontinuity resulted from rigidity difference between adjacent materials, smear effect and complicated boundary conditions should be considered in the behavior analysis of foundation behavior. The results of numerical analysis were influenced by smear zone. In relevant to this effect, finite element analysis was carried out using the reduced horizontal coefficient of permeability in the smear zone; The numerical results were compared with observed values in surface settlement. including pore water pressure. However only lateral di5plaoement by numerical ana1Ysis was shown since its measurement was not performed in the field. The predication of settlement to be developed later can be effectively employed for the obtimization of construction. The predication of residual settlement using the data measured in the field was made by Hoshino, Asaoka and hyperbolic method. Among them, the hyperbolic method proved best one. Settlements accorded well between numsrical and observed values while pore pressure showed a slight difference. Lateral displacement showed largest values at constant distance from ground surface. The validation of foundation analysis improved with pack drain by computer program employed in this study selecting modified Cam-clay model was satisfactorily secured.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.2
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• pp.59-68
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• 2001

A water balance analysis was performed for a paddy field neighboring the Dongchang stream, downstream of the Unmun reservoir, which is constructed for the urban water supply. Daily rainfall data were collected and irrigation water flow rate, drainage flow rate, evaportranspiration, infiltration, and piezometeric head were measured in the field. The flow rates were continuously observed by water level logger during the growing season. The evaportranspiration and the infiltration were measured by N-type depletion meter and cylindrical infiltrometer, respectively. PVC pipes with 12mm diameter were used for piezometric head measurement. Total Irrigation and drainage flows were 3,608mm and 1,170mm in 1999, and 3,971mm and 1,548mm in 2000, respectively. The mean and range of the daily infiltration rate were 4.4mm/d and 3.4mm/d to 5.5mm/d in 1999 and 5.1mm/d and 4.1mm/d to 6.5mm/d in 2000, respectively. The net ground water flow including the change of soil water storage was 2,855mm in 1999 and 2,540mm in 2000. The evapotranspiration was 458.3mm in 1999 and 553.5mm in 2000. The range of daily evapotranspiration rate was from 1.6 to 8.7mm/d. The return flow ratio was about 32% in 1999 and 39% in 2000 and three year average was 35% including previous study in 1997. The amount of irrigation water was much higher than design standards or references in this study, This was caused by the inadequate water management practice in the area where water was oversupplied on farmers’ request rather than following sound water management principles.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.3
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• pp.2029-2034
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• 1970

This research was attempted to study on the effects of desalinization by the depth and interval of open conduit in Kang-Hwa polder where is located at the Kil-sang Myun, Kang-Hwa Gun, Kyung-gi Do, and it has been continued for the three years from 1967 to 1969. The results obtained are as follows; 1. The depths of saline expulsion by supplying of irrigation water are approximately 30cm to 50cm under the ground surface, but saline expulsion is hardly done in case of the depth which is deeper than the above mentioned, because the moisture and saline content hardly change in such a condition. 2. The speed of vertical percolation gradually decreases below the 30cm depth, but it is noticed that there is a tendency to make the percolation of the horizental direction from its layer in Kang-Hwa reclaimed tidal land. 3. Comparing experimental treatments-varing depths and intervals of open conduits, the interval of open conduit has a more effect upon the promotion of desalinization and increasing of the rice yields than the depth of it. Therefore, according to the results of experimental data, the optimum depth of open conduit is about 0.9m, the effective interval of it is about 18m. 4. Considering the loss of arable area by the layout of open conduit, the reasonable interval of it could extend to 36m.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.102-111
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• 1998

Large amount of sludge have been generating in the process of water and wastewater treatment in urban area, and it has been making many environmental problems. Currently almost of sludge is landfilled, and since sludge is difficult to handle and dehydrate, the permeated water from the filled-in ground contaminate the surrounding soil and groundwater which may cause serious environmental and sociological problems. The organic component in sludge can be almost removed through the heat treatment process, and the final product is called artificial soil or artificial media according to the temperature control. To produce artificial media using sludge, chabazite and lime were used as an additive, and the mixture of sludge & additives was thermally treated in the firing kiln at about 800~1, 100。C for about fifteen minutes. The physical and chemical characteristics of the produced artificial media were analyzed, and it showed that it can be used as an artificial media for plant production or soil conditioner for farmland. The concentrations of the toxic heavy metals in the artificial media were lower than the soil quality standard for farmland. The characteristics of produced artificial media, using the mixture of sludge and additives through the heat treatment, is similar to the natural chabazite and soil. The analyzed result of the mineral composition of artificial media showed that it has a characteristics similar to natural stable soil, so the produced artificial media may be applied to farmland or water culture without causing adverse effect. Therefore this study showed that the above process can be a feasible alternative for sludge treatment.