• Journal of the Korean association of regional geographers
• /
• v.23 no.1
• /
• pp.168-177
• /
• 2017

In order to reveal formation factors and developmental processes of tafoni this study was conducted with petrological analysis including microscopic observation, measurement of water content and water analysis at Golgulsa temple in Gyeongju, South Korea. The direction of the entrance to tafoni at Golgulsa temple tends to coincide with the direction of slope, and this is thought to be related to the direction of wind flow and water supply. Tafoni's initial developmental processes is judged to have grown as a result of a breakaway of rock fragments along with beddings and cracks in rock. Then, tafoni have been enlarged along at the spots that sufficiently accommodate water supply depending on the direction of wind. The results of water analysis of the stagnant water in gnamma implies that a high meltage of Na and Cl compared to other inland areas can be from the adjacent shore. The effects of such saline substances on rock weathering and development of taponi are currently under way through electronic microscopy and geochemical analysis.

• Korean Journal of Environmental Biology
• /
• v.32 no.3
• /
• pp.234-242
• /
• 2014

In this study, gametotoxicity and embryotoxicity experiments using Hemicentrotus pulcherrimus were carried out to investigate the ecotoxicological effects of bisphenol A (BPA). We examined the effects of BPA on fertilization and normal embryogenesis at various concentrations (0, 300, 500, 800, 1000, and 1500 ppb). The results demonstrated that the fertilization rates were not changed. The normal embryogenesis rates were gradually decreased in a dose-dependent manner, and were significantly lowered following 800 ppb BPA treatment ($EC_{50}$=1056.1 ppb, 95% Cl=981.8~1163.9 ppb). The observed effective concentration and the lowest observed effective concentration of the normal embryogenesis rate were 500 ppb and 800 ppb, respectively. The embryos showed retarded development at each tested concentration, indicating the fact the embryonic development was delayed due to the increasing concentrations of BPA. Furthermore, we examined the expression of glutathione S-transferase (GST) mRNA at various concentrations of BPA in H. pulcherrimus. Interestingly, it was found that the expression level of GST mRNA was significantly increased in the experimental group exposed to BPA. Based on these results, we suggested that BPA at greater than 800 ppb has a toxic effect during the early embryonic stages of H. pulcherrimus, and GST mRNA may be used as a biomarker for risk assessment of BPA contamination.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.14 no.6
• /
• pp.77-90
• /
• 2015

An increasing number of vehicles is causing various traffic problems such as chronic congestion of highways and air pollution. Local governments have been managing traffic by constructing systems such as Intelligent Transport Systems (ITS) and Advanced Traffic Management Systems (ATMS) to relieve such problems, but construction of an infrastructure-based traffic system is insufficient in resolving chronic traffic problems. A more sophisticated system with enhanced operational management capabilities added to the existing facilities is necessary at this point. As traffic patterns of the urban traffic flow is time-specific due to the different vehicle populations throughout the time of the day, a local network-wide signal operation plan that can manage such situation-specific traffic patterns is deemed to be necessary. Therefore, this study is conducted for the purpose of establishment of a plan for contextual signal control management through signal optimization at the network level after setting the Frame Signal in accordance to the traffic patterns gathered from the short-term traffic forecast data as a means to mitigate the problems with existing standardized signal operations.

• The KIPS Transactions:PartD
• /
• v.14D no.7
• /
• pp.707-718
• /
• 2007

Recently, much studies for providing mobile users with suitable and useful content services, LBS(Location Based Service) corresponding to the change of users' location, are actively going on. First and foremost, this is basically owing to the progress of location management technologies such as GPS, mobile communication technology and the spread of personal devices like PDA and the cellular phones. Besides, the research scope of LBS has been changed from vehicle tracking and navigation services to intelligent and personalized services considering the changing information of conditions or environment where the users' are located. For example, it inputs the information such as heavy traffic, pollution, and accidents. The query languages which effectively search the stored vehicle and environment information have been studied depending on the increase of the information utilization. However, most of existing moving object query languages are not enough to provide a recommendation service for a user, because they can not be tested and evaluated in real world and did not consider changed environment information. In order to retrieve not only a vehicle location and environment condition but also use them, we suggest a moving object query language for recommendation service and implement a moving object query process system for supporting a query language. It can process a nearest neighbor query for recommendation service which considers various attributes such as a vehicle's location and direction, environment information. It can be applied to location based service application which utilizes the recommended factors based on environmental conditions.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.2
• /
• pp.183-200
• /
• 2022

A variety of simulation approaches based on automated driving technologies have been proposed to develop traffic operations strategies to prevent traffic crashes and alleviate congestion. The maneuver of simulated autonomous vehicles (AVs) needs to be realistic and be effectively differentiated from the behavior of manually driven vehicles (MVs). However, the verification of simulated AV maneuvers is limited due to the difficulty in collecting actual AVs trajectory and interaction data with MVs. The purpose of this study is to develop a methodology to evaluate the suitability of AV maneuvers based on both driving and traffic simulation experiments. The proposed evaluation framework includes the requirements for the behavior of individual AVs and the traffic stream performance resulting from the interactions with surrounding vehicles. A driving simulation approach is adopted to evaluate the feasibility of maneuvering of individual AVs. Meanwhile, traffic simulations are used to evaluate whether the impact of AVs on the performance of traffic stream is reasonable. The outcome of this study is expected to be used as a fundamental for the design and evaluation of transportation systems using automated driving technologies.

• Journal of Life Science
• /
• v.32 no.9
• /
• pp.721-728
• /
• 2022

This study investigated the diversity of intestinal microbial communities isolated from the intestine of topshell (Turbo cornutus) from the coast of Jeju Island (Beobhwan, Seogwipo city). Pure cultivation using the standard marine agar (MA) medium showed the most significant number of clusters. Aerobic and anaerobic culture allowed isolation of strains of 1.8×10⁵ CFU·g^-1 and 0.4×10 CFU·g^-1 on average, respectively. The microbial population in the topshell intestine was classified into 4 phyla, 12 families, 26 genera, and 67 species. The microbes in the topshell intestine were detected by homology with 93~100% with standard strains. The microbes in the topshell intestine consisted of Proteobacteria 39%, Firmicutes 34%, Actinobacteria 21%, and Bacteroidets 6%. The identified families were Alteromonadaceae (1), Shewanellaceae (4), Vibrionaceae (12), Phyllobacteriaeceae (1), Rhodobacteraceae (8), Bacillaceae (21), Paenibacillaceae (2), Cellulomonadaceae (1), Mycobacteriaceae (6), Nocardiaceae (4), Streptomycetaceae (3) and Flavobacteriaceae (4). Bacillus sp. and Vibrio sp. accounted for the greatest portion of the separated strains. Among the isolated microorganisms, some strains had probiotic functions.

• Journal of Korean Society of Transportation
• /
• v.29 no.5
• /
• pp.121-138
• /
• 2011

More affordable and available cutting-edge technologies (e.g., wireless vehicle communication) are regarded as a possible alternative to the fixed infrastructure-based traffic information system requiring the expensive infrastructure investments and mostly implemented in the uninterrupted freeway network with limited spatial system expansion. This paper develops an advanced decentralized traveler information System (ATIS) using vehicle-to-vehicle (V2V) communication system whose performance (drivers' travel time savings) are enhanced by three complementary functions (autonomous automatic incident detection algorithm, reliable sample size function, and driver behavior model) and evaluates it in the typical $6{\times}6$ urban grid network with non-recurrent traffic state (traffic incident) with the varying key parameters (traffic flow, communication radio range, and penetration ratio), employing the off-the-shelf microscopic simulation model (VISSIM) under the ideal vehicle communication environment. Simulation outputs indicate that as the three key parameters are increased more participating vehicles are involved for traffic data propagation in the less communication groups at the faster data dissemination speed. Also, participating vehicles saved their travel time by dynamically updating the up-to-date traffic states and searching for the new route. Focusing on the travel time difference of (instant) re-routing vehicles, lower traffic flow cases saved more time than higher traffic flow ones. This is because a relatively small number of vehicles in 300vph case re-route during the most system-efficient time period (the early time of the traffic incident) but more vehicles in 514vph case re-route during less system-efficient time period, even after the incident is resolved. Also, normally re-routings on the network-entering links saved more travel time than any other places inside the network except the case where the direct effect of traffic incident triggers vehicle re-routings during the effective incident time period and the location and direction of the incident link determines the spatial distribution of re-routing vehicles.

• Journal of the Korean association of regional geographers
• /
• v.4 no.1
• /
• pp.43-56
• /
• 1998

The purpose of this study is to identify distributional characteristics of climatic elements and to analyze synoptic characteristics on the pressure fields for spring droughts in Korea. In the distributions of minimum temperature during the spring droughts, positive anomalies and negative anomalies are mixed up, but in March the negative anomaly areas are widely distributed in Korea. It implies that the droughts of March have more frequent occurrences of the west-high, east-low pressure patterns. In the maximum air temperatures, the positive anomalies appear in Korea. It indicates that the spring droughts have rain days, cloud amount and humidities less than normal. As a result, the amount of evaporation is increased in Korea. In the pressure anomaly of surface pressure fields, the positive anomalies appear in the west, negative anomalies in the east in March, but in May the positive anomalies appeared zonally around the Korean peninsula. It indicates that March droughts have more frequent occurrences of the west-high. east-low patterns, but in May the Korean Peninsula has more frequent recurrences of the migratory anticyclone patterns. The height anomaly patterns of 500hPa pressure surface in spring droughts are similarly shown to those of surface fields. In March droughts, the positive height anomalies appear in the west, the negative height anomalies in the east, but in April the negative height anomaly areas are extended to the west part. In May the positive anomalies appear zonally around the Korean Peninsula, and strong positive height anomalies appear around the Kamchatka Peninsula and the sea of Okhotsk. These are the result of circulations that inhibit the eastward movement of westerlies and that has persistent anticyclone circulation patterns around the Korean Peninsula. As a result, the zonal indices of westerlies during March and April droughts are lower than normal, but higher in May. These data indicate that early spring droughts are associated with weak zonal flow, but the late spring droughts are obviously related with strong zonal flow. In addition, during early spring droughts the abnormally deep trough over the west coast of the North Pacific Ocean that accompanied the anticyclone was associated with frequent advection of air from the dry regions in the Central Asia into the Korean Peninsula. The atmospheric circulation patterns at the height of the 500hPa pressure surface in May was quite different from March and April circulation patterns. Instead of the abnormal ridge in the west and trough in the east, the circulation pattern in May was characterized by a much stronger than normal anticyclone over the Korean Peninsula. Also, the zonal indices of westerlies in May are higher than normal. The occurrences of drought in early spring, therefore, have mechanism different from those of late spring.

• Childhood Kidney Diseases
• /
• v.9 no.2
• /
• pp.222-230
• /
• 2005

Purpose : ARC syndrome refers to an association of arthrogryposis, renal tubular dysfunction, and cholestasis. The VPS33B gene was recently identified as the causative gene. So far, 41 cases of ARC syndrome have been reported worldwide, and it has rarely been reported in Korea. This study was conducted to report the clinical findings of seven ARC syndrome cases in Korean children, focusing especially on renal tubular dysfunction. Methods : The hospital records of 7 cases diagnosed as ARC syndrome at Severance Hospital between Mar. 1995 and Aug. 2005 were reviewed and analyzed. Results : Of the 7 cases, 4 were boys and 3 were girls. Six patients(85$\%$) were born with normal birth weight at term, and one was born at preterm. All cases presented with cholestasis and severe jaundice. According to the type of arthrogryposis described by Brown et al, type 3 and 4 were found in 2 patients and type,6, 7, and the undistributed type in one patient respectively. Other associated clinical findings were as follows : failure to thrive in 6(85$\%$), lax skin in 5(71$\%$), and gray platelet syndrome in 4(57$\%$). Urine analysis revealed 6 cases(85$\%$) with proteinuria, 3(43$\%$) with hematuria, 5(71$\%$) with glycosuria, 2(29$\%$) with phosphaturia and 2(29$\%$) with calciuria. Serum electrolytes showed 4 cases(57$\%$) with hyponatremia, 3(43$\%$) with hypokalemia, and 1(14$\%$) with creatinine elevation. Renal tubular dysfunctions were diagnosed as renal tubular acidosis in 6 cases(85$\%$), nephrogenic diabetes insipidus in 2(29$\%$), and Fanconi syndrome in 2(29$\%$). During the follow-up period, 2(29$\%$) had no treatment, 5(85$\%$) had continuous supplementation to correct the electrolyte imbalance and acidosis, and 1(14$\%$) had dialysis. Only one patient had a family history of ARE syndrome in a sibling. Four cases(57$\%$) were diagnosed at the mean age of 8.2 months, and one case was lost during follow-up. Ages of the survived 2 cases were 13 and 25 months, respectively. Conclusion : The rare disease of ARC syndrome Is associated with severe renal dysfunction. However, this study revealed that the renal manifestation of ARC syndrome in Korean children is relatively mild and survival rate is higher than that of previous studies. Contrary to previous reports, this study showed that familial cases are rare and sporadic occurence is possible in Korea. Thus, the diagnosis of this syndrome requires a careful evaluation of the venal function in cases of congenital arthrogryposis, and a mandatory genetic counseling of affected family for prevention of familial occurance. (J Korean Soc Pediatr Nephrol 2005;9:222-230)

• Journal of Korean Society of Forest Science
• /
• v.89 no.5
• /
• pp.618-629
• /
• 2000

This study was carried out to investigate ecological niche of Quercus acuta communities in Bogildo-island from July to October, 1998. This island is occupied by a subtropical evergreen broad-leaved forests. The study on community ecology of Q. acuta, mostly dominant species of subtropical forests, is very important for successful forest management. Sampling areas were selected in 16 quadrats, dominated by Q. acuta to examine the vegetation characteristics(plant identification, D.B.H.) and environmental elements (microtopography, altitude, slope degree, aspect, illumination and soil physicochemical properties). On the basis of data from field surveys, importance values were calculated for the dominance of Q. acuta and volume growth was analyzed by tree ring widths. The results obtained were as follows ; 1. The lists of vascular plants in the investigations were identified as 54 families, 91 genera, 113 species, 9 varieties, 1 formae. It appeared that 45 kinds were evergreen, 6 kinds(Camellia japonica, Ligustrum japonicum, Eurya japonica, Smilax china, Trachelospermum asiaticum var. intermedium, Carex lanceolata) were commonly observed in all plots and 5 species(Cinnamomum japonicum, Ardisia japonica, Cymbidium goeringii, Dryopteris bissetiana, Viburnum erosum) were most highly observed in all plots(over 80%). 2. The dominating species per strata were, Quercus acuta, Castanopsis cuspidata sp. Quercus salicina, Pinus thunbergii, Prunus sargentii in tree layer, Camellia Japonica, Ligustrum japonicum, Quercus acuta, Eurya japonica, Castanopsis cuspidata sp. in subtree layer, Camellia japonica, Ligustrum japonicum, Smilax china, Cinnamomum japonicum, Viburnum erosum in shrub layer and Trachelospermum asiaticum var. intermedium, Ardisia japonica, Carex lanceolata, Camellia japonica(seedlings), Quercus acuta(seedlings) in herb layer, all in descending orders. 3. Quercus acuta could be suggested as shade intolerant tree, considering the distribution in southern, western, nothern and eastern slopes in the descending orders. 4. Mean relative illumination in the forest is 0.89 % and it is relatively low in brightness. 5. Sustainment of Quercus acuta community couldn't be confirmed by judging from their reverse J curve in even-aged forest, as shown in D.B.H. distribution analysis. 6. The result of annual ring width analysis(mean ; 2.44 mm) showed three stages, such as a gentle increasing(1~12 year ; 2.04 mm), a relatively steep increasing(13~22 year ; 2.95 mm) and decreasing or stagnating(23 year after ; 2.41 mm).