A framework for identifying spatiotemporal hot spots of speculative land transactions using prospective monitoring procedures: the case of South Korea

Abnormally high-priced transactions in urban land speculation bring detrimental effects on economy, environment, and society. Governmental agencies around the world are striving hard to monitor and control land speculation by introducing various policy objectives and tools for an efficient urban development planning. One of the major challenges in controlling land speculation is to quickly identify the spatiotemporal locations of concern (hot spots) by monitoring the spatial clustering pattern changes over time and to alert the appropriate decision-making agencies for timely policy intervention. In this paper, we introduce a framework to rapidly detect the spatiotemporal hot spots of speculative land transactions in near-real-time data by exploiting the prospective monitoring procedures. We applied this method in the city of Hwasung, Republic of Korea, as an empirical illustration and found that the locations Jeongnam, Bongdam, Mado, and Dongtan were identified as hot spots with high, concentrated transaction values. The results indicate that the proposed framework is a capable tool for capturing prospective temporal indicators and pinpointing the localities of land speculation.     

Exploratory Spatiotemporal Analysis in Risk Communication during the MERS Outbreak in South Korea

The 2015 Middle East respiratory syndrome (MERS) outbreak in South Korea gave rise to chaos caused by psychological anxiety, and it has been assumed that people shared rumors about hospital lists through social media. Sharing rumors is a common form of public perception and risk communication among individuals during an outbreak. Social media analysis offers an important window into the spatiotemporal patterns of public perception and risk communication about disease outbreaks. Such processes of socially mediated risk communication are a process of meme diffusion. This article aims to investigate the role of social media meme diffusion and its spatiotemporal patterns in public perception and risk communication. To do so, we applied analytical methods including the daily number of tweets for metropolitan cities and geovisualization with the weighted mean centers. The spatiotemporal patterns shown by Twitter users' interests in specific places, triggered by real space events, demonstrate the spatial interactions among places in public perception and risk communication. Public perception and risk communication about places are relevant to both social networks and spatial proximity to where Twitter users live and are interpreted in reference to both Zipf's law and Tobler's law.     

Practical spreading of driving forces for wave-driven currents

Profiles of wave-induced current on plane beaches are generally smooth. Previously, the smooth nature was often explained by involving lateral mixing concept. This paper describes a new spreading approach instead of the previous lateral mixing approach. The spreading of the driving forces leads to similar results on the velocity profiles of the previous approach. The results of the new method show good agreement with some laboratory measurements for a plane beach. The present method was then extended for two-dimensional plan problems. The present approach was tested against a laboratory experiment, and the computed flow field agrees reasonably well with the measured flow field. A merit of the present method is that the computational time increment is not restricted by the lateral mixing.     

Physiography and deposition on a distal deep-sea system: The Valencia Fan (Northwestern Mediterranean)

The Valencia Fan developed as the distal fill of a deep-sea valley, detached from the continental slope and the main sedimentary source. A survey of side-scan sonar, Sea Beam and reflection seismics shows that the sediment is largely fed through the Valencia Valley. The upper fan comprises large channels with low-relief levees, and the middle fan has sinuous distributary channels. Depositional bedforms predominate on the valley floor and levees, and erosional bedforms are common in the valley walls. A change to slope on the fan apex and the presence of volcanoes on the upper fan are the main factors influencing fan-growth pattern.     

Effect of Moisture on Attraction Force in Beach Sand

Beach sands located above the sea water level exist in an unsaturated, rather than a fully saturated or dry state. Within the unsaturated zone, a steep excavated surface can be sustained for some unknown but finite time, and some slopes may remain stable for extended time periods due to capillary forces. These observations clearly indicate small but nonzero values for attraction strength (tensile strength and cohesion) in unsaturated beach sands, especially apparent but not confined to settings where there are low stress levels. Thus, experiments were carried out to quantify the magnitude of attraction strength in moist sands (D_r = 30%) and to examine the variation of these values as a function of moisture content and presence of a small amount of fines. Tensile strength, which is significantly different from zero, increases with increasing moisture content and fines. However, the influences of fines on the tensile strength are substantially dependent on the water content. Apparent cohesion strength is also identified in moist sands. A simple relationship between tensile strength and apparent cohesion is proposed using the obtained data. This study would help to further understand the phenomenon of stability of beach sands.     

Seasonal Dynamics of Phytoplankton and Environmental Factors around the Chagwi-do off the West Coast of Jeju Island,Korea

The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at 10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in the marine ranching area from September 2004 to November 2005. Water temperature varied from 12.1 to 28.9°C (average 18.8°C), and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was 0.02-2.05 μg L¹ (average 0.70 μg L¹), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to 10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae, 13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was 2.21-48.69x10⁴ cells L¹ (average 9.23x 10⁴ cells L¹), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking in November. The spring bloom was represented by fourChaetoceros species andSkeletonema costatum; each contributed 10–20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates, of which dinoflagellates were predominant.Gymnodinium conicum, Prorocentrum micans, andP. triestinum each contributed over 10% of the total phytoplankton abundance.     

Identifying late Quaternary coastal deposits in Kyonggi Bay, Korea, by their geotechnical properties

Based on cone penetration tests with pore pressure measurements (CPTUs) and standard penetration tests (SPTs), the geotechnical properties of five lithostratigraphic units were determined during the construction of Incheon international airport on reclaimed macrotidal flats in Kyonggi Bay, Korea. Two late Pleistocene non-marine units (unit V and unit IV) display largest N values (cf. number of blows required to achieve a standard penetration), reflecting coarse-grained and overconsolidated sediments. Tidal channel and tidal flat facies (unit IIIb) consist of unweathered late Pleistocene tidal sand and mud. The tidal channel facies is characterized by upward-decreasing cone resistance (q _t) and sleeve friction (f _s) with negative pore pressures (u _bt), reflecting a fining-upward textural trend. The tidal flat facies, by contrast, is represented by uniformly low q _t and f _s values with high friction ratios (FRs), suggesting homogeneous muddy deposits. Two overconsolidated units, a weathered late Pleistocene tidal mud (unit IIIa) and an early Holocene organic-rich non-marine mud (unit II), are characterized by high q _t, f _s, FRs and N values, unit IIIa being much more consolidated than unit II. Holocene tidal sands and muds (unit I) show the smallest q _t and f _s values with positive u _bt. These are slightly more consolidated than the tidal flat facies of unit IIIb. Two unconformable boundaries (a sequence boundary and a transgressive surface) have also been identified on some CPTU and SPT profiles. The boundaries are indicated by gradual but sharp increases in q _t, f _s and N values with an abrupt drop of u _bt, which indicates the contact between two units showing contrasting rigidity. The regional pattern produced by the unconformable boundaries indicates the presence of late Pleistocene valleys which pass through the middle of study area. The location of the valleys seems to be controlled by the antecedent basement morphology.     

Genomic cloning and expression of vitellogenin gene from the self-fertilizing fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae)

We cloned the vitellogenin gene from the self-fertilizing fish Rivulus marmoratus, and sequenced 12,326 bp. The number of exons of R. marmoratus and rainbow trout vitellogenin genes were different, and also the splicing junctions are different throughout most of the exons and introns but the amino acid similarity of R. marmoratus vitellogenin gene to other species was rather high. In promoter region of R. marmoratus vitellogenin gene, there were several E2 binding sites and the estrogen response element (ERE). We discuss here the gene structure and expression of R. marmoratus vitellogenin gene.     

Development of internet-based ship technical information management system

In this paper, internet-based ship technical information management system has been developed as a means to accumulate, manage, share and utilize various distributed applications and information used for ship design and building. The information managed in the system is documents from the whole life cycle including concept design, basic design, detailed design, construction, operation and maintenance. In addition, using the developed system, integrated system framework is also proposed to integrate applications and database in concurrent engineering environment.     

Hydroelastic response of a very large floating structure over a variable bottom topography

An influence of sea-bottom topography on the hydroelastic response of a Very Large Floating Structure (VLFS) is considered. When the floating structure is constructed near the shore, the sea-bottom topographical effect should be considered. In this study, the effect of sea-bottom topography is investigated for four different bottom cases. To calculate the sea-bottom effects rigorously, the finite-element method based on the variational formulation is used in the fluid domain. The pontoon-type floating structure is modeled as the Kirchhoff plate. The mode superposition method is adopted for the hydroelastic behavior of the floating structure.