• Journal of the Korean Geophysical Society
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• v.4 no.2
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• pp.87-93
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• 2001

The roof tiles excavated from the mountain fortress at Namsan-ri Seocheon-gun in Chungnam province were dated by using SAR protocol, Sample preparation was done with the quartz exclusion method. The paleodoses from 6 kinds of roof tiles were obtained from OSL measurements and the does rates of the soil around the excavated roof tiles and the tile themselves were measured from ICP/MS and ICP/AES with the conversion table. From the evaluated paleodose and the dose rate, the age of the roof tiles were determined to be from(733 ± 50)AD to (1160 ± 50)AD and the error was less than 10%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1883-1892
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• 1998

This paper considers the efficient design of routing path and wavelength assignment asignment in the sigle-hop WDM optical transport networks. The connecton demands between node-pairs are given and a connection must be made by only one lightpath. It is assumed that no wavelength conversion is allowed and the physical topology of the network is given. This paper proposes a method to find the routes of lightpaths and assign wavelengths to the routes, which minimizes the number of total wavelength to satisfy all connection demands. We establish a new optimization model that finds the minimum number of wavelengths. A heuristic algorithm with polynomial iterations is developed for the problem. The algorithm is implemented and applied to the netowrks with real problem size. The results of the application are compared with the commericial optimization solver, GAMS/OSL and Wauters & Demeester [8].

• Journal of the Korean earth science society
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• v.36 no.3
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• pp.222-235
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• 2015

Samples were collected from both places including the coastal area within the height of 5 m above the mean sea level (msl) (DH) and the top of the coastal terrace of 10-15 m msl (KS) high in Gwangseungri, Gochanggun, Korea. To find the origin of the deposit in the coastal area, granulometric analysis and geochemical analysis were performed. The result showed that the DH samples were originated from the reddish soils overlaying weathered bedrock which presented gradual change of chemical composition from the bottom toward the top. Clay minerals were found from the DH samples. These results concluded that the DH samples were found as in-situ weathered materials. The KS samples were originated from the soil layer covering gravel layer at the foot slope of the hill along the coast. The KS samples contained different chemical compositions from the DH. It is inferred that some of this layer was disturbed or experienced the influx of foreign material. The particle size of the KS samples was different from those found on the beach. The particle size of lower parts of KS site was finer than that on the beach, but the particle size of middle part of the site was coarser than that on the beach. The sorting of the KS site was poorer than that on the beach. Thus, it is inferred that some parts of the layer were formed by short-lived high energy event rather than sustained and continuous action of tidal currents and/or waves. Analysis using an optically stimulated luminescence (OSL) method showed that the burial age of samples from KS site were found 0.65-0.71 ka. Though the characteristics of the sediment layer and forming event in this area should be further studied, it can be inferred that this sedimentary layer formed by coastal flooding with storm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.7
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• pp.22-27
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• 2001

In this paper, the complex permittivity of various dielectrics such as powder(sugar and flour) and solid(teflon and acrvl) are measured by using an open ended coaxial-line probe, which is self designed and manufactured, The probe is connected to a vector network analyzer(VNA) through a coaxial cable, The end of the cable is corrected by using an OSL(open, short, and load) calibration kit, The phase difference, which is produced by inserting the probe at the end of the line. is compensated by using the numerically calculated reflection coefficient of distilled water, The complex permittivity is reconstructed by inserting the measured reflection coefficient, which is produced at the interface between the probe and measuring material, into ,an virtual conical cable conversion model. Over a wide frequency range from 30 MHz to 3 GHz, the measured complex permittivitis of various powder and solid using the our method are compared with the results, which are measured by using an transmission-line method of the Korea Research Institute of Standards and Science(KRISS).

• Journal of The Geomorphological Association of Korea
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• v.17 no.2
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• pp.87-98
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• 2010

There have been growing concerns for the sea level rise due to global warming in recent years. Sea level rise is a serious problem to densely populated coastal areas, because it may affect the coastal landforms to be damaged. Especially coastal sand deposits like coastal dunes are more sensitive than the other coastal landforms. In this paper, Ground Penetrating Radar (GPR) and Optically Stimulated Luminescence (OSL) dating method were used to identify the Holocene geomorphic changes of coastal dune field in Shinduri located at the western coast. The main results in this study that are the dunefield in the study area may have begun to form at around 6.8 ka and it has grown seaward thereafter. Then, dunefield appears to have extensively developed since 3.7 ka. This result, together with previous works on the sea level and climatic changes in the western coast of Korea suggest that the dunefield has been affected by the sea level regression since the Holocene high stand in the Holocene at around 6 ka and climatic change from warm and humid to cold and dry conditions occurred at 4.5 ka.

• Journal of the Korean association of regional geographers
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• v.22 no.3
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• pp.703-713
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• 2016

This study documents the altitude of paleo-shoreline and formation age of the $1^{st}$ marine terrace emerged around Heunghae-eup Pohang City (South Korea). As a result, the $1^{st}$ terrace representing 10 m of the paleo-shoreline was formed at MIS 5c around 100,000 BP and was influenced repetitive sedimentation of sea-wave till regression of MIS 5a. The result is recognized as a definite truth for the $1^{st}$ terrace in the eastern coast of the Korean peninsula based on synthetic reviews of previous studies and cross-validation of absolute age data. Furthermore, this study deduces a sea stand at MIS 5c from the geomorphological contrast method, but precise determination of paleo-shoreline of the $2^{nd}$ terrace should be required to estimate that of MIS 5c.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.222-228
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• 2016

Background: We are developing a small size dosimeter for dose estimation in particle therapies. The developed dosimeter is an optical fiber based dosimeter mounting an radiation induced luminescence material, such as an OSL or a scintillator, at a tip. These materials generally suffer from the quenching effect under high LET particle irradiation. Materials and Methods: We fabricated two types of the small size dosimeters. They used an OSL material Eu:BaFBr and a BGO scintillator. Carbon ions were irradiated into the fabricated dosimeters at Heavy Ion Medical Accelerator in Chiba (HIMAC). The small size dosimeters were set behind the water equivalent acrylic phantom. Bragg peak was observed by changing the phantom thickness. An ion chamber was also placed near the small size dosimeters as a reference. Results and Discussion: Eu:BaFBr and BGO dosimeters showed a Bragg peak at the same thickness as the ion chamber. Under high LET particle irradiation, the response of the luminescence-based small size dosimeters deteriorated compared with that of the ion chamber due to the quenching effect. We confirmed the luminescence efficiency of Eu:BaFBr and BGO decrease with the LET. The reduction coefficient of luminescence efficiency was different between the BGO and the Eu:BaFBr. The LET can be determined from the luminescence ratio between Eu:BaFBr and BGO, and the dosimeter response can be corrected. Conclusion: We evaluated the LET dependence of the luminescence efficiency of the BGO and Eu:BaFBr as the quenching effect. We propose and discuss the correction of the quenching effect using the signal intensity ratio of the both materials. Although the correction precision is not sufficient, feasibility of the proposed correction method is proved through basic experiments.

• Journal of The Geomorphological Association of Korea
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• v.23 no.3
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• pp.41-55
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• 2016

The granulometric characteristics and chemical composition of the samples from the Bukpyeong myeon, Hainam gun, Jeollanam do were analyzed in this study. The samples were collected from the outcrop of coastal area where the height is about 30m. The burial age of the sediments also estimated by OSL(Optically Stimulated Luminescence) method. The origin and forming processes of the samples are not clear in this stage as limited number of evidences can be found. However it is suggested that the samples are not aeolian deposits originated from chinese loess by the chemical analysis. The mean diameter of samples were $5{\sim}6{\varphi}(silt)$ and are increased slightly downwards. The samples also well sorted. The samples have been heavily weathered by the chemical alteration index. The value of CIA increase downward rapidly at the upper part of outcrop, then stabilized afterwards. The vertical concentration changes ratio of cations varies; Si increases downwards while Fe, Ti, K and Mg decrease. There are fluctuation in concentration ratio of Na and Ca with increasing depth. The burial age of sample from upper part are estimated as $104.52{\pm}4.45ka\;BP$, while that of lower part are $136.10{\pm}6.52ka\;BP$, and they fall in to last part of MS6. The deposition rate for this site is found about 0.017mm/year. The uplift rate of the site is supposed to be 0.24~0.26m/ka with assumption of palaeo-sea level of +6m. However the origin of the sediment deposits should be explored and cleared.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.17-35
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• 1997

This paper considers the efficient design of routing path and wavelength assignment in the single-hop WDM optical transport networks. The connection demands between node-pairs are given and a connection between a pair of nodes must be made by only one lightpath. It is assumed that no wavelength conversion is allowed and the physical topology of the network and the number of available wavelengths of a physical link are also given. This paper proposes the method to route a path and assign a wavelength to the path, which guarantees fairness to every node pair. In order to guarantee fairness and maximize connections, an optimization model is established, which successively maximizes minimum connection ratio to the demand of each node pair. A heuristic algorithm with polynomial iterations is developed for the problem since the problem is NP-hard. The heuristic algorithm is implemented and applied to the networks with real problem sizes. The results of the application are compared with GAMS/OSL.

• Journal of The Geomorphological Association of Korea
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• v.23 no.1
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• pp.17-33
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• 2016

Samples from newly exposed outcrop of sedimentary layers forming Jeongdongjin coastal terrace in Gangreung area are collected and analyzed to find the sedimentary environment. The site are located at the gentle hillslope of the terrace surface area. The height of the outcrop is about 8m and the altitude of it's highest part is 68~73m MSL. The lowest part of this out crop is the partly consolidated sand layer with gravel veneer within it. It is found that this part is not in-situ weathered sand stone through the OSL method. This sand layer is overlain by the gravel layer with sand matrix. The shapes of the gravels from this part are mainly 'platy', 'elongated', and 'bladed' by the index of Sneed and Folk(1958). In addition, mean roundness is not so high. It is sceptical to regard this part as marine sediments which are continuously exposed to erosional processes. The boundary between the lowest sand layer and gravel layer showing the abrupt change in forming material without any mixture or transitional zone, so gravels are seemed to deposited after some degree of consolidation of the lowest sand layer. In addition, the hight of the boundary between layers are changed by the place, so the surface of the partly consolidated sand layer is not flat and has irregularity on topography when it buried by gravels. Main part of this out crop is the poorly sorted coarse gravel(22.4mm) with sand matrix($1.36{\phi}$) layer with at least 2m thick covering the relatively fine gravels discussed above. Over 20% of particles have 'very platy', 'very elongated' and 'very bladed' shape and only less than 5% of particles have 'compact' shape, So this particles are also very hard to be regard as marine gravels which are abraded by marine processes. It can be concluded that this gravel layer formed by fluvial processes rather than coastal processes base on the form of the clast and sedimentary structure. The gravel layer is covered by fine($3{\sim}4{\phi}$) material layers of psudo-gleization which showing inter-bedding of red and white layers. Chemical composition of matrix and other fine materials should be analyzed in further studies. It is attempted to fine the burial ages of the sediment using OSL method, but failed by the saturation. So it can be assumed that these sediments have be buried over 120ka.