• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.111-112
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• 2009

Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.305-309
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• 2012

Purpose:This study was conducted to research any effect on aided distance visual acuity and refractive error changes by using smartphone at near for long term. Methods: 20($20.6{\pm}0.9$ years) young adults subjects with no ocular diseases, over 0.8 of aided distance visual acuity, normal amplitude of accommodation and normal accommodative facility agreed to participate in this study. The subjects were divided into two group, Group 1 (15 cm fixation distance) included 10 subjects and Group 2(40 cm fixation distance) included 10 subjects. Aided distance visual acuity and refractive error were measured before and after using smartphone for 30 minutes by auto-chart project (CP-1000, Dongyang, Korea), phoropter (VT-20, Dongyang, Korea), auto refractor-keratometer (MRK-3100, Huvitz, Korea). After then, the subjects looked at distance with wearing spectacles. Refractive error was measured at 5 minutes, 10 minutes, and 15 minutes later, respectively. Results: After using smartphone at 15 cm for 30 minutes, there was statistically significant reduction of aided distance visual acuity (p=0.030) and increasing myopia (p=0.001). The increased myopia was not statistically significant after 5 minutes rest (p${\geq}$0.464). However there was no statistically significant changes in aided distance visual acuity (p=0.163) and refractive error (p=0.077) after using smartphone at 40 cm for 30 minutes. Conclusions: It is recommend to keep 40 cm off the smartphone from eyes to avoid any aided distance visual acuity and refractive error changes. If smartphone is used closer than 40 cm, a rest for 5 minutes is also recommend after every 30 minutes use with smartphone to avoid any aided distance visual acuity and refractive error changes.

• Journal of Preventive Medicine and Public Health
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• v.42 no.2
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• pp.96-103
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• 2009

Objectives : We evaluated the health effects of exposure to BTEX(Benzene, Toluene, Ethylbenzene, m,p-Xylene, o-Xylene) in the Taean area after the Hebei Spirit oil spill. Methods : We used a questionnaire survey to look for health effects among 80 pregnant women 2 to 3 months following the Hebei Spirit oil spill. Their BTEX exposures were estimated using the CALPUFF method. We then used a multiple logistic regression analysis to evaluate the effects of BTEX exposure on the women s health effets. Results : Pregnant women who lived near the accident site reported more symptoms of eye irritation and headache than those who lived farther from the site. There was a trend of decreasing symptoms with an increase in distance from the spill site. Pregnant women exposed to higher ambient cumulative levels of Xylene were significantly more likely to report symptoms of the skin(OR 8.01 95% CI=1.74-36.76) in the first day after the accident and significantly more likely to report abdominal pain(OR 3.86 95% CI=1.02-14.59 for Ethylbenzene, OR 6.70 95% CI=1.82-24.62 for Xylene) during the 1st through 4th days following the accident. Conclusions : This study suggests that exposure to BTEX from an oil spill is correlated with an increased risk of health effects among pregnant women. This implies the need to take proper measures, including the development of a national policy for environmental health emergencies and a plan for studying the short- and long-term chronic health effects associated with such spills.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.271-283
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• 2006

A systematic water quality survey was conducted in August, 2005 for a drinking water supply reservoir (the Jeolgol reseuoir located in an island), which is at an early stage of impoundment, to investigate the causes of water color deterioration of the reservoir and the clogging of filter beds of a water treatment plant. The reservoir shape was simple and its average depth was 5.5 m, increasing from upreservoir toward the downreservoir end near the dam. Dissolved oxygen (DO) and chloropllyll-a (chi-a) showed a large variation while water temperature had a smaller range. Transparency ranged from 0.6 to 0.9 m (average 0.7 m). The average value of turbidity was 9.3 NTU, ranging from 8.0 ${\sim}$ 12.1 NTU. The transparency and the turbidity appear to be affected by a combination of biological and non-biological factors. The poor transparency was explained by an increase of inorganic colloids and algal bloom in the reservoir. The blockage of the filter bed was attributed to the oversupply of phytoplanktons from the reservoir. The range and the average concentration of chi-a within the reservoir were 31.6 ${\sim}$ 258.9 ${\mu}g\;L^{-1}$, 123.6 ${\mu}g\;L^{-1}$ for the upper layer, and 17.0 ${\sim}$ 37.4 ${\mu}g\;L^{-1}$, 26.5 ${\mu}g\;L^{-1}$ for the bottom layer, respectively. A predominant species contributing the algal bloom was Dinophyceae, Peridinium bipes f. occultatum. The distribution of Peridinium spp. was correlated with chi-a concentrations. The standing crop of phytoplankton was highest in the upreservoir with $8.5\;{\times}\;103\;cells\;mL^{-1}$ and it decreased toward the downresevoir. Synedra of Bacillariophyceae and Microcystis aeruginosa of Cyanophyceae appeared to contribute to the algal bloom, although they are not dominated. It is mostly likely that sloped farmlands located in the watershed of the reservoir caused water quality problems because they may contain a significant amount of the nutrients originated from fertilizers. In addition, the aerators installed in the reservoir and a shortage of the inflowing water may be related to the poor water quality. A long-term monitoring and an integrated management plan for the water quality of the watersheds and the reservoir may be required to improve the water quality of the reservoir.

• Korean Journal of Acupuncture
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• v.19 no.1
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• pp.15-23
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• 2002

This study was carried to identify the component of Large Intestine Meridian Muscle in human, dividing into outer, middle, and inner part. Brachium and antebrachium were opened widely to demonstrate muscles, nerve, blood vessels and the others, displaying the inner structure of Large Intestine Meridian Muscle. We obtained the results as follows; 1. Meridian Muscle is composed of the muscle, nerve and blood vessels. 2. In human anatomy, it is present the difference between a term of nerve or blood vessels which control the muscle of Meridian Muscle and those which pass near by Meridian Muscle. 3. The inner composition of meridian muscle in human arm is as follows. 1) Muscle; extensor digitorum tendon(LI-1), lumbrical tendon(LI-2), 1st dosal interosseous muscle(LI-3), 1st dosal interosseous muscle and adductor pollicis muscle(LI-4), extensor pollicis longus tendon and extensor pollicis brevis tendon(LI-5), adductor pollicis longus muscle and extensor carpi radialis brevis tendon(LI-6), extensor digitorum muscle and extensor carpi radialis brevis mucsle and abductor pollicis longus muscle(LI-7), extensor carpi radialis brevis muscle and pronator teres muscle(LI-8), extensor carpi radialis brevis muscle and supinator muscle(LI-9), extensor carpi radialis longus muscle and extensor carpi radialis brevis muscle and supinator muscle(LI-10), brachioradialis muscle(LI-11), triceps brachii muscle and brachioradialis muscle(LI-12), brachioradialis muscle and brachialis muscle(LI-13), deltoid muscle(LI-14, LI-15), trapezius muscle and supraspinous muscle(LI-16), platysma muscle and sternocleidomastoid muscle and scalenous muscle(LI-17, LI-18), orbicularis oris superior muscle(LI-19, LI-20) 2) Nerve; superficial branch of radial nerve and branch of median nerve(LI-1, LI-2, LI-3), superficial branch of radial nerve and branch of median nerve and branch of ulna nerve(LI-4), superficial branch of radial nerve(LI-5), branch of radial nerve(LI-6), posterior antebrachial cutaneous nerve and branch of radial nerve(LI-7), posterior antebrachial cutaneous nerve(LI-8), posterior antebrachial cutaneous nerve and radial nerve(LI-9, LI-12), lateral antebrachial cutaneous nerve and deep branch of radial nerve(LI-10), radial nerve(LI-11), lateral antebrachial cutaneous nerve and branch of radial nerve(LI-13), superior lateral cutaneous nerve and axillary nerve(LI-14), 1st thoracic nerve and suprascapular nerve and axillary nerve(LI-15), dosal rami of C4 and 1st thoracic nerve and suprascapular nerve(LI-16), transverse cervical nerve and supraclavicular nerve and phrenic nerve(LI-17), transverse cervical nerve and 2nd, 3rd cervical nerve and accessory nerve(LI-18), infraorbital nerve(LI-19), facial nerve and infraorbital nerve(LI-20). 3) Blood vessels; proper palmar digital artery(LI-1, LI-2), dorsal metacarpal artery and common palmar digital artery(LI-3), dorsal metacarpal artery and common palmar digital artery and branch of deep palmar aterial arch(LI-4), radial artery(LI-5), branch of posterior interosseous artery(LI-6, LI-7), radial recurrent artery(LI-11), cephalic vein and radial collateral artery(LI-13), cephalic vein and posterior circumflex humeral artery(LI-14), thoracoacromial artery and suprascapular artery and posterior circumflex humeral artery and anterior circumflex humeral artery(LI-15), transverse cervical artery and suprascapular artery(LI-16), transverse cervical artery(LI-17), SCM branch of external carotid artery(LI-18), facial artery(LI-19, LI-20)

• Korean Journal of Acupuncture
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• v.20 no.4
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• pp.65-75
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• 2003

This study was carried to identify the component of Spleen Meridian Muscle in human, dividing into outer, middle, and inner part. Lower extremity and trunk were opened widely to demonstrate muscles, nerve, blood vessels and the others, displaying the inner structure of Spleen Meridian Muscle. We obtained the results as follows; 1. Spleen Meridian Muscle is composed of the muscle, nerve and blood vessels. 2. In human anatomy, it is present the difference between a term of nerve or blood vessels which control the muscle of Meridian Muscle and those which pass near by Meridian Muscle. 3. The inner composition of meridian muscle in human arm is as follows ; 1) Muscle; ext. hallucis longus tend., flex. hallucis longus tend.(Sp-1), abd. hallucis tend., flex. hallucis brevis tend., flex. hallucis longus tend.(Sp-2, 3), ant. tibial m. tend., abd. hallucis, flex. hallucis longus tend.(Sp-4), flex. retinaculum, ant. tibiotalar lig.(Sp-5), flex. digitorum longus m., tibialis post. m.(Sp-6), soleus m., flex. digitorum longus m., tibialis post. m.(Sp-7, 8), gastrocnemius m., soleus m.(Sp-9), vastus medialis m.(Sp-10), sartorius m., vastus medialis m., add. longus m.(Sp-11), inguinal lig., iliopsoas m.(Sp-12), ext. abdominal oblique m. aponeurosis, int. abd. ob. m., transversus abd. m.(Sp-13, 14, 15, 16), ant. serratus m., intercostalis m.(Sp-17), pectoralis major m., pectoralis minor m., intercostalis m.(Sp-18, 19, 20), ant. serratus m., intercostalis m.(Sp-21) 2) Nerve; deep peroneal n. br.(Sp-1), med. plantar br. of post. tibial n.(Sp-2, 3, 4), saphenous n., deep peroneal n. br.(Sp-5), sural cutan. n., tibial. n.(Sp-6, 7, 8), tibial. n.(Sp-9), saphenous br. of femoral n.(Sp-10, 11), femoral n.(Sp-12), subcostal n. cut. br., iliohypogastric n., genitofemoral. n.(Sp-13), 11th. intercostal n. and its cut. br.(Sp-14), 10th. intercostal n. and its cut. br.(Sp-15), long thoracic n. br., 8th. intercostal n. and its cut. br.(Sp-16), long thoracic n. br., 5th. intercostal n. and its cut. br.(Sp-17), long thoracic n. br., 4th. intercostal n. and its cut. br.(Sp-18), long thoracic n. br., 3th. intercostal n. and its cut. br.(Sp-19), long thoracic n. br., 2th. intercostal n. and its cut. br.(Sp-20), long thoracic n. br., 6th. intercostal n. and its cut. br.(Sp-21) 3) Blood vessels; digital a. br. of dorsalis pedis a., post. tibial a. br.(Sp-1), med. plantar br. of post. tibial a.(Sp-2, 3, 4), saphenous vein, Ant. Med. malleolar a.(Sp-5), small saphenous v. br., post. tibial a.(Sp-6, 7), small saphenous v. br., post. tibial a., peroneal a.(Sp-8), post. tibial a.(Sp-9), long saphenose v. br., saphenous br. of femoral a.(Sp-10), deep femoral a. br.(Sp-11), femoral a.(Sp-12), supf. thoracoepigastric v., musculophrenic a.(Sp-16), thoracoepigastric v., lat. thoracic a. and v., 5th epigastric v., deep circumflex iliac a.(Sp-13, 14), supf. epigastric v., subcostal a., lumbar a.(Sp-15), intercostal a. v.(Sp-17), lat. thoracic a. and v., 4th intercostal a. v.(Sp-18), lat. thoracic a. and v., 3th intercostal a. v., axillary v. br.(Sp-19), lat. thoracic a. and v., 2th intercostal a. v., axillary v. br.(Sp-20), thoracoepigastric v., subscapular a. br., 6th intercostal a. v.(Sp-21)

• Journal of Distribution Science
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• v.10 no.5
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• pp.7-17
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• 2012

The recent announcement of the National Research Foundation of Korea (NRF) to cease journal accreditation operations as of the end of the year 2014 can easily influence the future of many research journals in Korea. Although this plan has not yet been formalized or structured, its facilitation would be the major turning point for the current Korean research and scholarly journals and publications. In addition, the NRF's plan to select and fund top 20 or more research journals over the five year period beginning 2015 suggests that the competition will most likely increase among Korean journals. Each journal would need to develop its unique strategy to improve and strengthen its competitiveness to become or maintain its position as a major research journal in Korea. The association of Korean Distribution of Science (KODISA) and its research journal, Journal of Distribution Science (JDS), has been continuously improving its reputation as a reputable journal in the distribution and related fields since its establishment in 1999. Due to demand, JDS has had to undergo several changes in its publication cycle first from semiannual publication to quarterly, then finally to monthly publications in 2012, and has become one of the major social science journals in Korea. Furthermore, with the redesigning of its webpage with English language in July of 2011, KODISA has made the published journals freely accessible and available to both domestic and foreign researchers, scholars, practitioners, and learners. These changes have resulted in the rapid increase in the bounce rate and the number of journal submissions by foreign scholars, with four research articles having been submitted by foreign scholars just in March of 2012 alone. However, although the changes and outcomes have resulted in a reasonable success so far, the achievement may only become a short-term success without continuously developing, improving, and implementing both effective and efficient strategies through critical, thorough, and frequent examinations and evaluations of both KODISA and JDS. As such, the purpose of this research is to carefully examine both KODISA and JDS to identify problematic factors and to develop appropriate strategies to change or modify those problems for further strengthening and improving their reputation and status. The paper examines and analyzes the past, present, and future of KODISA and JDS and their managerial, operational, and systematic procedures and operations. The narrow scope of research and inefficiencies in promoting the association and the journal and the improvement of impact factors are identified as the notable problems that could hinder JDS from being included in SCOPUS or SSCI in the near future. This type of examination and exploration has not been previously conducted, so the major limitation of this paper can be identified as not meticulously elaborating on the problems nor proving detailed recommendations based on the existing researches. This article asserted that solving the problem of the narrow scope of research would lead to facilitation of resolving other inefficient problems. Inclusion of international academic disciplines to the distribution and their related fields would be the viable initiation of expanding the research area, and this strategy could promote the journal as well as improve its impact factors. The narrow scope of research seems to be a good research topic and merit further exploration as an individual research project, because this kind of research could yield the creation of new understandings or theories.

• The Journal of Fisheries Business Administration
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• v.40 no.2
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• pp.49-70
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• 2009

This study proviedes GARCH model(Bollerslev, 1986) to analyze the structural characteristics of price volatility in domestic aquacultural fish market of Korea. As a case study, flatfish and rock-fish are analyzed as major species with relatively high portion in an aspect of production volume among fish captured in Korea. For analyzing, this study uses daily market data (dating from Jan 1 2000 to June 30, 2008) published by the Noryangjin Fisheries Wholesale Market which is located in Seoul of Korea. This study performs normality test on trading volume and price volatility of flatfish and rock-fish as an advanced empirical approach. The normality test adopted is Jarque-Bera test statistic. As a result, first, a null hypothesis that "an empirical distribution follows normal distribution" was rejected in both fishes. The distribution of daily market data of them were not only biased toward positive(+) direction in terms of kurtosis and skewness, but also characterized by leptokurtic distribution with long right tail. Secondly, serial correlations were found in data on market trading volume and price volatility of two species during very long period. Thirdly, the results of unit root test and ARCH-LM test showed that all data of time series were very stationary and demonstrated effects of ARCH. These statistical characteristics can be explained as a reasonable ground for supporting the fitness of GARCH model in order to estimate conditional variances that reveal price volatility in empirical analysis. From empirical data analysis above, this study drew the following conclusions. First of all, from an empirical analysis on potential effects of seasonality and the day of week on price volatility of aquacultural fish, Monday effects were found in both species and Thursday and Friday effects were also found in flatfish. This indicates that Monday is effective in expanding price volatility of aquacultural fish market and also Monday has higher effects upon the price volatility of fish than other days of week have since it has more new information for weekend. Secondly, the empirical analysis led to a common conclusion that there was very high price volatility of flatfish and rock-fish. This points out that the persistency parameter($\lambda$), an index of possibility for current volatility to sustain similarly in the future, was higher than 0.8-equivalently nearly to 1-in both flatfish and rock-fish, which presents volatility clustering. Also, this study estimated and compared and model that hypothesized normal distributions in order to determine fitness of respective models. As a result, the fitness of GARCH(1, 1)-t model was better than model where the distribution of error term was hypothesized through-distribution due to characteristics of fat-tailed distribution, was also better than model, as described in the results of basic statistic analysis. In conclusion, this study has an important mean in that it was introduced firstly in Korea to investigate in price volatility of Korean aquacultural fishery products, although there was partially a limited of official statistic data. Therefore, it is expected that the results of this study will be useful as a reference material for making and assessing governmental policies. Also, it is looked forward that the results will be helpful to build a fishery business plan as and aspect of producer, and also to take timely measures to potential price fluctuations of fishery products in market. Hence, it is advisable that further studies related to such price volatility in fishery market will extend and evolve into a wider variety of articles and issues in near future.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.3
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• pp.69-80
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• 2012

The purpose of this paper was to study the issues related to converting the graveyards within forests into spaces intended for tree burials by means of planting, given the situation that the graveyards have encroached on land and damaged the environment. For the reason, a field survey was performed to determine the width, length, and distance to the nearest tree of 205 graveyards in the capital area. Through this, it was determined that the domestic lands damaged by graveyards amounted to $862km^2$, including the areas that were deforested to manage the graves. This only confirms that land encroachment by graveyards is a serious issue. The methods for making tree burial sites were examined from the perspective of how to meet public demands given the graveyard's spatial distinctiveness. As a result, this study suggested different methods to establish tree burial sites according to the degree of transformation and the term of its formation. This study also classified the graveyards into three types, and identified the planting methods that harmonized the safe growth of trees and the scenic beauty of memorial places based on the standard. This is in order to plant trees that are shade-tolerant and suitable to the forest line, along with which other tree line was and also, to plant aesthetic trees around the empty space. Through applying the developed methods, this study established and monitored two exemplary sites in Yongin and Boryeng. Aesthetic trees were planted in Yongin site which was located in an open area, aod the shade-tolerant trees were planted in Boryeong, which was located in a forest area. As a result, the image of a garden appeared at Yongin site and the image of a tree colony harmonized with the near forest emerged at Boryeong site. Therefore, it is confirmed that the method of planting according to the distribution status of neighboring trees was effective. As a result of monitoring, mulching wood chips were suitable for sites that were small or easy to approach. This is because the weeds were controlled in Yongin site by mulching. Furthermore, by monitoring the growth of 11 species of vegetation, this study confirmed that low and cover-type vegetations were suitable for tree burial sites. In Boryeong site, the wild cherry trees, which were planted as adult trees, all died, and the tilling of snake's beard, which were planted as cover vegetation, was slow. Therefore, this study found that seedlings were more suitable to plant in forest graveyards than adult trees, which were large and difficult to approach, and it was effective to use the remaining lawn and form a low vegetation after the crown of trees had expanded to such places.

• Journal of the Korean Institute of Navigation
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• v.4 no.2
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• pp.45-79
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• 1980

The aim of this paper is to analyze the mechanics of price formation in the tramp shipping. For the purpose of this study, the main characteristics of tramp freight rates and the market is examined, and a brief examination of the nature ofthe costs of operation is given which are essential for the understanding of the functioning of shipping firms as well as for the understanding of developments in the tramp freight market. The demand and supply relationships in the market is also analysed in detail. Tramp shipping is an industry that has a market which functions under conditions that are not dissimilar to the theoretical model of perfect competition. However, it does notmean that tramp shipping market is a perfectly competitive market. It is apparent that this realworld competitive system has its imperfections, which means that the market for tramp shipping is near to being a perfectly competitive market on an internaitonal scale and it is freight are therefore subjext to the laws of supply and demand. In theory, the minimum freight rate in the short term is that at which the lowest cost vessels will lay-up in preference to operating, and is equal to the variable costs minus lay-up costs; and this would imply that in all times except those of full employment for ships there is a tendency for newer low-cost, and, probably, faster vessels to be driving the older high-cost vessels in the breaker's yards. In this case, shipowners may be reluctant to lay-up their ships becasue of obligations to crews, or because they would lose credibility with shippers or financiers, or simply because of lost prestige. Mainly, however, the decision is made on strictly economic grounds. When, for example, the total operating costs minus the likely freight earnings are greater than the cost of taking the ship out of service, maintaining it, and recommissioning it, then a ship may be considered for laying-up; shipowners will, in other words, run the ships at freight earnings below operating costs by as much as the cost of laying them up. As described above, the freight rates fixed on the tramp shipping market are subject to the laws of supply and demand. In other words, the basic properties of supply and demand are of significance so far as price or rate fluctuations in the tramp freight market are concerned. In connection with the same of the demand for tramp shipping services, the following points should be brone in mind: (a) That the magnitude of demand for sea transport of dry cargoes in general and for tramp shipping services in particular is increasing in the long run. (b) That owning to external factors, the demand for tramp shipping services is capable of varying sharphy at a given going of time. (c) The demad for the industry's services tends to be price inelastic in the short run. On the other hand the demand for the services offered by the individual shipping firm tends as a rule to be infinitely price elastic. In the meantime, the properties of the supply of the tramp shipping facilities are that it cannot expand or contract in the short run. Also, that in the long run there is a time-lag between entrepreneurs' decision to expand their fleets and the actual time of delivery of the new vessels. Thus, supply is inelastic and not capable of responding to demand and price changes at a given period of time. In conclusion, it can be safely stated that short-run changes in freight rates are a direct result of variations in the magnitude of demand for tramp shipping facilities, whilest the average level of freight rates is brought down to relatively low levels over prolonged periods of time.