• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1610-1619
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• 1998

The ABR service class provides feedback based traffic control to transport bursty data traffic efficiently. Feedback based congestion control has first been studied to be applied to unicast connections. Recently. several congestion control algorithms for multicast connections have also been proposed as the number of ABR applications requiring multicast increases. With feedback based congestion control, the effectiveness of a traffic control scheme diminishes as propagation delay increases. Especially for a multicast connection, a remote destination may suffer unfair service compared to a local destination due to the delayed feedback. Amelioration of the disadvantages caused by feedback delay is therefore more important for remote destinations in multicast connections. This paper proposes a new switch behavior to provide effective feedback based mathc control for rentoh destinations. The proposed switches adjust the service rate dynamically in accordance woth the state of the downstream, that is, the congestion of the destinaion is immediately controlled by the nearest apstream switch before the source to ramp down the transmission rate of the connection. The proposed switch has an implementation overhead to have a separate buffer for each VC to adjust the service rate in accordance with a backward Rm cell of each VC. The buffer requirement id also increased at intermediate switches. Simulation results show that the proposed switch reduces the cell loss rate in both the local and the remote destinations and slso amelioratd the between the two destinations.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.137-148
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• 2006

The purpose of this study was to compare muscle activity in the lower extremity during walking wearing jogging and roller shoes. Twelve male middle school students (age: 15.0 yrs, height 173.7 cm, weight 587.7 N) who have no known musculoskeletal disorders were recruited as the subjects. Seven pairs of surface electrodes (QEMG8, Laxtha Korea, gain = 1,000, input impedance >$1012{\Omega}$, CMMR >100 dB) were attached to the right-hand side of the body to monitor the rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and medial (GM) and lateral gastrocnemius (GL) while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and EMG recordings. EMG data were filtered using a 10 Hz to 350 Hz Butterworth band-passdigital filter and further normalized to the respective maximum voluntary isometric contraction EMG levels. For each trial being analyzed, five critical instants and four phases were identified from the recording. Averaged IEMG and peak IEMG were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p<.05). The VM, TA, BF, and GM activities during the initial double limb stance and the initial single limb stance reduced significantly when going from jogging shoe to roller shoe condition. The decrease in EMG levels in those muscles indicated that the subjects locked the ankle and knee joints in an awkward fashion to compensate for the imbalance. Muscle activity in the GM for the roller shoe condition was significantly greater than the corresponding value for the jogging shoe condition during the terminal double limb stance and the terminal single limb stance. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the GM activity for the roller shoe condition increased. It seems that there are differences in muscle activity between roller shoe and jogging shoe conditions. The differences in EMG pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine joint kinematics during walking with roller shoes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.143-149
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• 1996

Forecasts of the monthly catches of anchovy in Korea were carried out by the seasonal Autoregressive Integrated Moving Average (ARIMA) model and spectral analysis. The seasonal ARIMA model is as follows: $$(1-0.431B)(1-B^{12})Z_t=(1-0.882B^{12})e_t$$ where: $Z_t=value$ at month $t;\;B^{p}$ is a backward shift operator, that is, $B^pZ_t=Z_{t-p};$ and $e_t=error$ term at month t, which is to forecast 24 months ahead the anchovy catches in Korea. The prediction error by the Box-Cox transformation on monthly anchovy catches in Korea was less than that by the logarithmic transformation. The equation of the Box-Cox transformation was $Y'=(Y^{0.58}-1)/0.58$. Forecasts of the monthly anchovy catches for $1991\~1992$, which were compared with the actual catches, had an absolute percentage error (APE) range of $1.0\~63.2\%$. Total observed annual catches in 1991 and 1992 were 170,293 M/T and 168,234 M/T respectively, while the predicted catches were 148,201 M/T and 148,834 M/T $(API\;13.0\%\;and\;11.5\%,\;respectively)$. The spectrum analysis of the monthly catches of anchovy showed some dominant fluctuations in the periods of 2.2, 6.1, 10.2 12.0 and 14.7 months. The spectrum analysis was also useful for selecting the ARIMA model.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.769-782
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• 2009

Stereoscopic video service is one of the most widely adopted technologies for 3-Dimensional technology. However, the stereoscopic video service has not been penetrated into the market since there does not exist a proper transmission method even though the conventional MPEG-2 Transport Stream (TS) has support for broadcast service of mono-scopic video contents. This is partly because the MPEG-2 TS does not support displaying a stereoscopic video content which consists of several composition types widely used in the market. This paper proposes the new MPEG-2 TS specification suitable for transmitting and displaying stereoscopic video contents. In order to show feasibility of the proposal, this paper describes an end-to-end system which is implemented with consideration of the method how to multiplex and de-multiplex stereoscopic video contents as well as keeping backward compatibility with the traditional MPEG-2 TS.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.3
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• pp.185-197
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• 2001

Recently, the design method by VHDL coding and synthesis has been used widely. As the integration ratio increases, the amount design by VHDL at a time also increases so many coding errors occur in a design. Thus, lots of time and effort is dissipated to detect those coding errors. This paper proposed a method to verify the coding errors in VHDL behavioral-level designs. As the methodology, we chose the method to detect the coding error by applying the generated set of verifying patterns and comparing the responses from the error-free case(gold unit) and the real design. Thus, we proposed an algorithm to generate the verifying pattern set for the coding errors. Verifying pattern generation is peformed for each code and the coding errors are classified as two kind: condition errors and assignment errors. To generate the patterns, VHDL design is first converted into the corresponding CDFG(Control & Data Flow Graph) and the necessary information is extracted by searching the paths in CDFG. Path searching method consists of forward searching and backward searching from the site where it is assumed that coding error occurred. The proposed algorithm was implemented with C-language. We have applied the proposed algorithm to several example VHDL behavioral-level designs. From the results, all the patterns for all the considered coding errors in each design could be generated and all the coding errors were detectable. For the time to generate the verifying patterns, all the considered designed took less than 1 ［sec］ of CPU time in Pentium-II 400MHz environments. Consequently, the verification method proposed in this paper is expected to reduce the time and effort to verify the VHDL behavioral-level designs very much.

• The Research Journal of the Costume Culture
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• v.12 no.3
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• pp.415-428
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• 2004

The purpose of this thesis was to develop torso patterns according to the physical types of men in 20s. The procedure and results are as follows; 1. Of the men in 20s meeting the national average of physique, 4 men were selected and classified into 2 physical types according to their chest and waist circumference drops. One group had 20㎝ drop (Y type) while the other had 16㎝ drop (N type). Through evaluation performed by clothing construction professionals on the 4 upper bodice blocks drafted according to the existent drafting method and dressed on the 4 men, several problems have been found. These problems were adjusted and supplemented to make two new blocks. The fit of the new blocks were evaluated and proved to be satisfactory. 2. The following is the adjustments made to the existent men's torso patterns which had been utilized as the objects the first evaluation experiment. ① Though the back waist length of the pattern from the existent drafting method covered the center back length of the body in both Y type and N type, the front length did not causing it to stand away from the body. To adjust this, 2.0㎝ has been added to the center front length of each pattern so that the waist line could make a bar level to the ground. ② The shoulder line of the pattern from the existent drafting method had the tendency to fall backward. To make the shoulder line to fall in place, it has been moved 1.0㎝ to the front. 0.5㎝ has been added to the should length. ③ The neckline had a tendency to climb up. It has been lowered by 0.5㎝ until the line touched the center front neck point. ④ Though different in degree, the neck circumference did not allow enough width for both physique type causing the neckline to pull at side neck point with diagonal crease. To adjust this, 0.3㎝ and 0.6㎝ has been added to the Y type and N type respectively so that the neckline would touch the side neck point and the neckline could naturally fall into its original position. ⑤ Though different in degree, there was not enough space at the armhole causing wrinkles around this area. Therefore, 0.25㎝ and 0.5㎝ has been added to the front and back of the armholes of the Y and N types respectively. The armhole was made 1.0㎝ deeper only for the N type. ⑥ 1.0㎝ in the front and 0.5㎝ in the back were added to the side scam for the Y type while 0.5㎝ in the front and 0.25㎝ in the back were added for N type. This eliminated the unwanted wrinkles to give the silhouette a smooth look.

• Journal of Korea Port Economic Association
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• v.24 no.1
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• pp.61-83
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• 2008

The meaning of "added value" refers to the contribution of the factors of production, i.e., land, labor, and capital goods, to raising the value of a product and corresponds to the incomes received by the owners of these factors. The importance of added value in service industry has been recognized as one of the critical factors to economic growth, even in logistics industry. But, it is hard to find out the previous studies providing a clear definition and framework for designing and analyzing the performance of Value Added Logistics(VAL). The purpose of this study is to define the meaning of extended VAL that extensively includes activities initiating and operating the reverse logistics under the closed-loop logistic scheme, and to suggest the framework that describes the partnerships among participants involving in operating the value added logistics. Also, in this paper, we emphasize on the need for investigation of added value logistics definition and framework based on previous academic studies, and examine various value added logistics service activities of current leading 3PL companies across the world. Finally, we suggest the analytic framework for value added logistics throughout closed-loop logistics.

• Journal of Korea Port Economic Association
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• v.29 no.1
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• pp.77-97
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• 2013

This paper focuses upon the relationship between port and port city. The purpose of this study is to theoretically review the relationship between port and its city, and to identify crucial policy directions for mutual development of port and the backward city in the case of Gwangyang Port (GP), Korea. The contents of this paper consist of five main sections: introduction; a concept of port-port city relationship; an analysis of the relationship between GP and its city; policy directions for GP city; conclusion. This study was mainly conducted by a literature review of the papers/reports and the analysis of secondary data. Significant policy strategies are associated with development of value-added logistics, expansion of additional port business, vitalization of port hinterlands, and establishment of port logistics clusters in terms of port economic function. Green port operation, improvements of coastal environment, establishment of port waterfronts, and conceptual port redevelopment master plan are included in the major port city development strategies in terms of sustainable development. Another major port city development strategies contain major port city master plan, institutional arrangements for port city development, specialized port city development policy, and formation of free trade port city in relation to integrated port-port city planning and management.

• Journal of Korea Port Economic Association
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• v.36 no.3
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• pp.21-38
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• 2020

Currently, in-port emissions are a serious problem in port cities. However, emissions, especially non-greenhouse gases, from the operation of cargo handling equipment (CHE) have received significant attention from scientific circles. This study estimates the amount of emissions from on-land port diesel-powered CHE in the Port of Incheon. With real-time activity data provided by handling equipment operating companies, this research applies an activity-based approach to capture an up-to-date and reliable diesel-powered CHE emissions inventory during 2017. As a result, 105.6 tons of carbon monoxide (CO), 243.2 tons of nitrogen oxide (NOx), 0.005 tons of sulfur oxide (Sox), 22.8 tons of particulate matter (PM), 26.0 tons of volatile organic compounds (VOCs), and 0.2 tons of ammonia (NH3) were released from the landside CHE operation. CO and NOx emissions are the two primary air pollutants from the CHE operation in the Port of Incheon, contributing 87.71% of the total amount of emissions. Cranes, forklifts, tractors, and loaders are the four major sources of pollution in the Port of Incheon, contributing 84.79% of the total in-port CHE emissions. Backward diesel-powered machines equipped in these CHE are identified as a key cause of pollution. Therefore, this estimation emphasizes the significant contribution of diesel CHE to port air pollution and suggests the following green policies should be applied: (1) replacement of old diesel powered CHE by new liquefied natural gas and electric equipment; (2) the use of NOx reduction after-treatment technologies, such as selective catalytic reduction in local ports. In addition, a systematic official national emission inventory preparation method and consecutive annual in-port CHE emission inventories are recommended to compare and evaluate the effectiveness of green policies conducted in the future.

• Journal of the Korean GEO-environmental Society
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• v.10 no.2
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• pp.21-28
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• 2009

A grouting method has been widely used in construction of large-scale structure to reduce permeability and reinforce the ground. If cement and grout material were not mixed well in the injection tip equipment, an opposite flow and interception state of the chemical grouting can occur. McG (Multi-mixing counterflow prevented Grouting, McG) method installed a special grouting device to allow better mixing of the grouting material(above fineness $6,000cm^2/g$) and prevent backward flow. The block of nozzle also diversify powder rate of cement. YSS (Youngil Special Silicate, YSS) that lowers $Na_2O$ and thereby increases durability was developed by gel-forming reaction material. The seepage state and unconfined compressive strength of the injection material using the special injection tip equipment was tested in this study. The results of this study showed that the uniaxial compressive strength, permeability, N-value, TCR and RQD were improved by this method. Engineering characteristics obtained by the special injection tip method will be compared with those by the other method through various field tests from now on.