• Economic and Environmental Geology
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• v.50 no.2
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• pp.159-170
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• 2017

The temporal and spatial temperature distribution of the heat storage mortar made of porous feldspar was measured and the thermal properties and electricity consumption were analyzed. For the experiment, two real size chambers (control model and test model) with hot water pipes were constructed. Two large scale models with hot water pipes were constructed. The surface temperature change of the heat storage layer was remotely monitored during the heating and cooling process using infrared thermal imaging camera and temperature sensor. The temperature increased from $20^{\circ}C$ to $30^{\circ}C$ under the heating condition. The temperature of the heat storage layer of the test model was $2.0-3.5^{\circ}C$ higher than the control model and the time to reach the target temperature was shortened. As the distance from the hot water pipe increased, the temperature gap increased from $4.0^{\circ}C$ to $4.8^{\circ}C$. The power consumed until the surface temperature of the heat storage layer reached $30^{\circ}C$ was 2.2 times that of the control model. From the heating experiment, the stepwise temperature and electricity consumption were calculated, and the electricity consumption of the heat storage layer of the test model was reduced by 66%. In the cooling experiment, the surface temperature of the heat storage layer of the test model was maintained $2^{\circ}C$ higher than that of the control model. The heat storage effect of the porous feldspar mortar was confirmed by the temperature experiment. With considering that the time to reheat the heat storage layer is extended, the energy efficiency will be increased.

• Journal of the Korean association of regional geographers
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• v.10 no.2
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• pp.407-427
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• 2004

The rapid innovation of information and communication technology and its sharp falling prices have brought about the expansion of the Internet, integrating the world as one space under converged space and time. This rapid expansion of the Internet and its application in the economy have spurred the emergence of the digital economy. The Internet has influenced strongly on the changes of not only economic activities but also political, social and cultural activities. In this context, a rapidly increasing Internet expansion renders the rhetoric about the death of distance and about the meaningless of geographical place. However, the development and expansion of Internet induces a growing digital divide among nations and also a spatial inequality in a nation as the supply of the Internet has concentrated towards demand-affluent large cities. A large gap of digital access has been occurred between high income and low income countries according to a measurement of the international digital access index. In a national level, the Internet backbone has been built around large cities which favor a large amount of the Internet demand, and the affordable accessibility of these cities for the Internet services has influenced strongly on the agglomeration of Internet related industries, further inducing the construction and investment of the Internet backbone into large cities as cumulative causation effects. As a result, the expansion of the Internet affects immensely on the changes of spatial structure in a nation resulting in the new spatial phenomena such as centralization, concentration and splintering in the digitalized space-economy.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.42
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• pp.133-160
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• 2009

In International trade the buyer and seller are normally separated from on another not only by distance but also by differences in language and culture. It is rarely possible for the performance of obligations to be simultaneous and the performance of contracts therefore calls for trust in a situation in which the parties are unlikely to feel able to trust each other unless they have a longstanding and successful relationship. Thus the seller under an international contract of sale will not wish to surrender documents of title to goods to the buyer until he has at least an assurance of payment, and no buyer will wish to pay for goods until he has received them. A gap of distrust thus exists which is often bridged by the undertaking of an intermediary known and trusted by both parties who will undertake on his own liability to pay the seller the contract price in return for the documents of title and then pass the documents to the buyer in return for the reimbursement. This is a common explanation of the theory behind the documentary letter of credit in which the undertaking of a bank of international repute serves as a "guarantee" to each party that the other will perform his obligations. The independence principle, also referred to as the "autonomy principle", is at the core of letter of credit or bank guarantee law. This principle provides that the letter of credit or bank guarantee is independent of the underlying contractual commitment - that is, the transaction that the credit is intented to secure - between the applicant and the beneficiary ; the credit is also independent of the relationship between the bank and its customer, the applicant. The most important exception to the independence principle is the doctrine of fraud in the transaction. A strict interpretation of the rule that the guarantee is independent of the underlying transaction would lead to the conclusion that neither fraud nor manifest abuse of rights by the beneficiary would constitute an objection to payment. There is one major problem related to "Independent guarantees", namely abusive or unfair callings. The beneficiary may make an unfair calling under the guarantee. The countermeasure of beneficiary's unfair calling divided three cases. First, advance countermeasure namely by contract. In other words, when the formation of the contract, the parties must insert the Force Majeure Clause, Arbitration Clause to Contract, and clear statement to the condition for demand calling. Second, post countermeasure namely by court. Many countries, including the United States, authorize the courts to grant an order enjoining the issuer from paying or enjoining the beneficiary from receiving payment under the guaranty letter. Third, Export Insurance. For example, the Export Credit Guarantees Department is prepared, subject to certain conditions, to cover the risk of unfair calling. Of course, KEIC in Korea is cover the risk of the all things for guarantees. On international projects, contractor performance is usually guaranteed by either a standby letters of credit or Independent guarantee. These instruments will be care the parties.

• Progress in Superconductivity
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• v.12 no.2
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• pp.88-92
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• 2011

[ $MgB_2$ ]superconducting sheets have been fabricated using powder roll compaction method. Sheet-type $MgB_2$ bulk samples were successfully fabricated using the pre-reacted $MgB_2$ powders. In this work, $MgB_2$ powders were compacted by two rotating rolls and squeezed out as a form of $MgB_2$ sheets of ~1 mm thickness. The rolling speed of 0.3-0.7 rpm and the gap distance of 0.3-0.8 mm between the two rollers were carefully controlled to get a full compaction of the powders into bulk $MgB_2$ sheets. The densities of $MgB_2$ sheets were 1.98-2.05 g/$cm^3$, which is 75.44-77.99 % of the theoretical value of 2.63 g/$cm^3$. And the density comparison was made compared to those of typical $MgB_2$ bulks from uni-axial pressing and $MgB_2$ wires from Powder-In-Tube processing.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.6
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• pp.225-231
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• 2016

The valence band maximum (VBM) and conduction band minimum (CBM) of Al-doped GaInAsSb alloys substrated on GaSb are calculated by using an analytic approximation based on the tight binding method. The relative positions of the VBM and CBM between Al-GaInASSb and GaSb determine band alignement type, valence band offset (VBO) and conductin band offset (CBO) for the heterojunctions. In this study, aluminium doping is assumed to be substituted in the cation site and limited up to 20 % because it can easily oxidize and degrade materials. It is found that the Al-doped alloys exhibit type-II band alignments over the entire composition range and make the band gaps increase, whereas the VBO and CBO decrease. The decreasing rate of VBO is higher than that of CBO, which implies the Al components play a decisive role in controlling electrons at the interface. The Al-dopled GaInAsSb alloy has a direct band gap induced by $E({\Gamma})$ with a considerable distance from the E(L) and E(X), however, $E({\Gamma})$ approaches to E(L) and E(X) in the high Sb concentration (Sb > 0.7-0.8) which might affect the electron mobility and degrade the optical quality.

• Korean journal of communication and information
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• v.26
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• pp.291-326
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• 2004

This study explores the process within which whereas the majority of Korean people agree on the principle of the unification policy, the opinions about the concrete policy alternatives related to the principle do not converge. To account for this phenomenon, a.k.a. 'the principle-policy puzzle in public opinion', this study constructs and tests a covariance structural model with the explanatory variables such as political knowledge, political ideology, authoritarian personality, social distance, and the evaluation of the president. In addition, the interaction effects of the interpretive frames regarding the unification policy and political knowledge along with the main effects of socio-demographic variables are tested to explain the degree to which people show the gap between the agreements on the unification principle and policy alternatives. A sample of 600 Seoul people are recruited to provide the data for the analysis of structural equation modeling. Ie was found that the proposed model receives empirical supports from the data. In particular, political knowledge and authoritarian personality play key roles in accounting for the complex process of public opinion in the 'principle-policy puzzle'. The findings were discussed in terms of the representations of the Engagement policy in the mass media and the public perception of them.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.9
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• pp.1083-1095
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• 1999

최근 처리기와 입출력 시스템의 속도 차이가 점점 커짐에 따라 버퍼 캐쉬의 효율적인 관리가 더욱 중요해지고 있다. 버퍼 캐쉬는 블록 교체 정책과 선반입 정책에 의해 관리되며, 각 정책은 버퍼 캐쉬에서 블록의 가치 즉 어떤 블록이 더 가까운 미래에 참조될 것인가를 결정해야 한다. 블록의 가치는 응용들의 블록 참조 패턴의 특성에 기반하며, 블록 참조 패턴의 특성에 대한 정확한 분석은 올바른 결정을 가능하게 하여 버퍼 캐쉬의 효율을 높일 수 있다. 본 논문은 각 응용들의 블록 참조 패턴에 대한 특성을 분석하고 이를 자동으로 발견하는 기법을 제안한다. 제안된 기법은 블록의 속성과 미래 참조 거리간의 관계를 이용해 블록 참조 패턴을 발견한다. 이 기법은 2 단계 파이프라인 방법을 이용하여 온라인으로 참조 패턴을 발견할 수 있으며, 참조 패턴의 변화가 발생하면 이를 인식할 수 있다. 본 논문에서는 8개의 실제 응용 트레이스를 이용해 블록 참조 패턴의 발견을 실험하였으며, 제안된 기법이 각 응용의 블록 참조 패턴을 정확히 발견함을 확인하였다. 그리고 발견된 참조 패턴 정보를 블록 교체 정책에 적용해 보았으며, 실험 결과 기존의 대표적인 블록 교체 정책인 LRU에 비해 최대 57%까지 디스크 입출력 횟수를 줄일 수 있었다.Abstract As the speed gap between processors and disks continues to increase, the role of the buffer cache located in main memory is becoming increasingly important. The buffer cache is managed by block replacement policies and prefetching policies and each policy should decide the value of block, that is which block will be accessed in the near future. The value of block is based on the characteristics of block reference patterns of applications, hence accurate characterization of block reference patterns may improve the performance of the buffer cache. In this paper, we study the characteristics of block reference behavior of applications and propose a scheme that automatically detects the block reference patterns. The detection is made by associating block attributes of a block with the forward distance of the block. With the periodic detection using a two-stage pipeline technique, the scheme can make on-line detection of block reference patterns and monitor the changes of block reference patterns. We measured the detection capability of the proposed scheme using 8 real workload traces and found that the scheme accurately detects the block reference patterns of applications. Also, we apply the detected block reference patterns into the block replacement policy and show that replacement policies appropriate for the detected block reference patterns decreases the number of DISK I/Os by up to 57%, compared with the traditional LRU policy.

• Journal of Distribution Science
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• v.13 no.5
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• pp.83-90
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• 2015

Purpose - This research aims to understand the different behaviors of consumers according to cognitive age. Specifically, this research is focused on pro-social behavior. Pro-social behavior is defined as behavior benefiting others, rather than behavior benefiting one's self. It often entails individual risk or cost, such as when giving resources to others, waiting in line, asking for or paying a fair price, or risking one's life in battle. Therefore, we sought to understand consumer psychology and cognitive age as a reflection of inner psychology. People frequently perceive themselves as younger or older than their chronological ages. This self-perceived or cognitive age is a subjective age perception independent of actual chronological age. The discrepancy degree between chronological and cognitive age represents how much individuals perceive themselves as younger than they are. This study examines the gap in donation intention based on cognitive age. In order to investigate cognitive age, composed of four sub-categories (feel-age, look-age, do-age, and interest-age), this study explores the differential donation intention based on cognitive age, which determines the relationship between the young age and old age. Research design, data, and methodology - Data research was conducted by gathering 216 survey samples, excluding those with unreliable answers. Data coding and cleaning were used and SPSS 19.0 software for the data analysis. The respondents were categorized into two types, younger cognitive ages and older cognitive ages. Additionally, we analyzed the moderating variables. In particular, we used cognitive age degree and congruency level (cognitive age low vs. cognitive age high) × (congruency close vs. congruency distant) between - subjects design. First, regression was done to verify the difference between chronological age and cognitive age. Second, a t-test was done to verify the difference of cognitive age level in donations. Third, ANOVA (analysis of variance) was done to verify the difference between cognitive age and congruency in donations. Last, ANOVA was done to verify the difference between cognitive age and moral judgments in donations. Result - The results show most respondents perceive themselves as younger than their chronological ages. In particular, older respondents feel they are younger than their actual age. Moreover, the result of the comparison between low degree and high degree groups of cognitive age, show high donations at the higher degree of cognitive age groups. In addition, the closer the distance to the beneficiaries, the higher the donation in high degree cognitive age groups. The higher moral judgment groups also show relatively high contributions in lower degree cognitive age groups. Conclusions - Donations belong to the category of pro-social behavior reflecting an individual's psychological state. Therefore, it is important in understanding cognitive age. This study implies that it is necessary to take into account both cognitive age and chronological age when segmenting donors. Moreover, this study confirmed that there are different factors affecting the motives behind donations. Thus, it may be utilized to create differential donation strategies.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.1
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• pp.12-18
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• 1985

In general the impulse sound sources of underwater generated by electric arc discharge had used static energy of the charged capacitors. The author proposed an underwater arc discharge sound source using secondary voltage of high voltage transformer without capacitors. The arc discharge device was composed of a high voltage transformer and a switching system. The impulse current in the primary turn of the high voltage transformer is controlled by the switching system and inductive current of the secondary turn in the high voltage transformer is used in making impulsive arc discharge. A series of experiment have been carried out to observe the acoustic characteristics of the impulse sound source generated by the arc discharge. The results obtained were as follows: 1. Secondary current at the time of arc discharge keeps after ohm's law in the beginning and the maximum current flows out as soon as arc discharge breaks out. 2. A time difference between a start of applied current and a generation of arc discharge sound is the 3msec and it is generated arc sound when breaking down electric insulation at maximum voltage. 3. The sharper the end of electrodes and the higher the secondary voltage, the higher the sound pressure level. 4. Arc discharge sound was generated even at the distance of 100cm between electrodes and was stably reproductive at the gap of 1cm to 100cm. 5. Electric arc discharge sound wave is a shock wave of pulse-width of 0.15msec and spectral distribution of it is plenty of low frequency components less than 10 KHz.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.2
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• pp.93-102
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• 2014

This quantitative research aims to examine the connectivity of forest networks in seven metropolitan cities of South Korea using a graph-theoretical approach. We first estimated an overall network connectivity at multi-scales (i.e., dispersal distances), ranging from 100 m to 20 km, and quantified the contribution of small forest patches (less than 10 ha) to the overall network connectivity by comparing networks according to the presence and absence of small ones. As a result, the cities were divided into two groups depending on the network connectivity; one group of cities with high connectivity such as Daegu, Daejeon, and Ulsan and the other group of cities with low connectivity including Gwangju, Busan, Seoul, and Incheon. The result showed that small forest patches, especially in the cities with low connectivity, played a key role as stepping stones that connect large forested patches, thereby contributing to maintaining connectivity. This study also suggests that large and well-connected forest areas may be the key factor to preserve the connectivity in the cities with high connectivity, while the cites with low connectivity are in need of some complementary strategies. Through the study, we suggest that the creation of new forest patches in the areas where a gap in connectivity presents is needed in order to improve connectivity; and that the conservation of the existing small forest patches is essential in order to maintain the current connectivity level.