• Journal of Distribution Science
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• v.14 no.3
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• pp.73-83
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• 2016

Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.

• Journal of Internet Computing and Services
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• v.9 no.1
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• pp.21-32
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• 2008

In this paper, we propose new modulation schemes using the conventional CACB (Constant Amplitude Coded Multicode Biorthogonal) modulation with constant amplitude property. Also the proposed modulation schemes supports high transmission data rate by increasing the spectral efficiency, In order to obtain the high spectral efficiency, the $Q^2$AM (Quadrature-Quadrature Amplitude Modulation) and CA-$Q^2$AM (Constant Amplitude-$Q^2$AM) are used. We explain the simplest combining modulation scheme of CACB and $Q^2$AM (i.e., CACB-$Q^2$AM). However, this modulation scheme cannot support the constant amplitude property. Hence the first CACB-CA-$Q^2$AM (or CACB-CA-$Q^2$AM I) modulation scheme is proposed for the constant amplitude property. In the modulation scheme, the redundant constant amplitude encoding (spectral efficiency decrease) is required. Therefore, the second CACB-CA-$Q^2$AM (or CACB-CA-$Q^2$AM II) modulation scheme is proposed retaining the constant amplitude and the spectral efficiency. Computer simulations show that the proposed CACB-CA-$Q^2$AM II is the efficient modulation scheme.

• Journal of Broadcast Engineering
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• v.20 no.3
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• pp.388-397
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• 2015

High Efficiency Video Coding (HEVC)/H.265 is a new video coding standard which is known as high compression ratio compared to the previous standard, Advanced Video Coding (AVC)/H.264. Due to achievement of high efficiency, HEVC sacrifices the time complexity. To apply HEVC to the market applications, one of the key requirements is the fast encoding. To achieve the fast encoding, exploiting thread-level parallelism is widely chosen mechanism since multi-threading is commonly supported based on the multi-core computer architecture. In this paper, we implement both the Tile-level parallelism and the Frame-level parallelism for HEVC encoding on multi-core platform. Based on the implementation, we present two approaches in combining the Tile-level parallelism with Frame-level parallelism. The first approach creates the fixed number of tile per frame while the second approach creates the number of tile per frame adaptively according to the number of frame in parallel and the number of available worker threads. Experimental results show that both improves the parallel scalability compared to the one that use only tile-level parallelism and the second approach achieves good trade-off between parallel scalability and coding efficiency for both Full-HD (1080 x 1920) and 4K UHD (3840 x 2160) sequences.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.377-379
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• 2018

In recent years, with the focus on the younger generation, a minimal life that pursues a simple and light life has attracted attention, and a product that occupies a small space and has high practicality attracts attention. Therefore, a lot of studies on small but realistic products are going on by combining plural products into one. In this study, we developed a smart stand that can save space on the desk. The stand is equipped with a smartphone holder, humidifier, negative ion generator, and speaker functions. Because of this study, it is expected that the efficiency of space and economy will be improved in a small house of one person.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.1
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• pp.51-58
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• 2007

This paper presented an adaptive pipeline architecture for a high-performance and low-power asynchronous processor. The proposed pipeline architecture employed a stage-skipping and a stage-combining scheme. The stage-skipping scheme can skip the operation of a bubble stage that is not used pipeline stage in an instruction execution. In the stage-combining scheme, two consecutive stages can be joined to form one stage if the latter stage is empty. The proposed pipeline architecture could reduce the processing time and power consumption. The proposed architecture supports multi-processing in the EX stage that executes parallel 4 instructions. We designed an asynchronous microprocessor to estimate the efficiency of the proposed pipeline architecture that was synthesized to a gate level design using a $0.35-{\mu}m$ CMOS standard cell library. We evaluated the performance of the target processor using SPEC2000 benchmark programs. The proposed architecture showed about 2.3 times higher speed than the asynchronous counterpart, AMULET3i. As a result, the proposed pipeline schemes and architecture can be used for asynchronous high-speed processor design

• Corrosion Science and Technology
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• v.18 no.6
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• pp.228-231
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• 2019

Aluminum and its alloys have been widely used in various fields because of low weight, high strength, good conductivity, and low price. It is well known that aluminum alloys that cause natural oxide film can inhibit corrosion in wet, salty environments. However, these oxides are so thin that corrosion occurs in a variety of environments. To prevent this problem, an electrochemical anodizing technique was applied to the aluminum alloy surface to form a thick layer of oxide and a unique oxide shape, such as a hierarchical pore structure simultaneously combining large and small pores. The shape of the structures was implemented using stepwise anodization voltages such as 40 V for mild anodizing and 80 V for hard anodizing, respectively. To maximize water repellency, it is crucial to the role of surface structures shape. And a hydrophobic thin film was coated by 1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane (FDTS) to minimize surface energy of the structure surface. Thus, such nanoengineered superhydrophobic surface exhibited a high water contact angle and excellent corrosion resistance such as low corrosion current density and inhibition efficiency.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.162-171
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• 2014

Spectrum sensing is a key technical challenge for cognitive radio (CR). It is well known that multicycle cyclostationarity (MC) detection is a powerful method for spectrum sensing. However, a conventional MC detector is difficult to implement because of its high computational complexity. This paper considers reducing computational complexity by simplifying the test statistic of a conventional MC detector. On the basis of this simplification process, an improved MC detector is proposed. Compared with the conventional detector, the proposed detector has low-computational complexity and high-accuracy sensing performance. Subsequently, the sensing performance is further investigated for the cases of Rayleigh, Nakagami-m, Rician, and Rayleigh fading and lognormal shadowing channels. Furthermore, square-law combining (SLC) is introduced to improve the detection capability in fading and shadowing environments. The corresponding closed-form expressions of average detection probability are derived for each case by the moment generation function (MGF) and contour integral approaches. Finally, illustrative and analytical results show the efficiency and reliability of the proposed detector and the improvement in sensing performance by SLC in multipath fading and lognormal shadowing environments.

• Journal of Korea Multimedia Society
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• v.18 no.6
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• pp.701-709
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• 2015

Image stitching method is a technique for obtaining an high-resolution image by combining two or more images. In X-ray image for clinical diagnosis, the size of the imaging region taken by one shot is limited due to the field-of-view of the equipment. Therefore, in order to obtain a high-resolution image including large regions such as a whole body, the synthesis of multiple X-ray images is required. In this paper, we propose a rapid stitching method of digital X-ray images using template-based registration. The proposed algorithm use principal component analysis(PCA) and k-nearest neighborhood(k-NN) to determine the location of input images before performing a template-based matching. After detecting the overlapping position using template-based matching, we synthesize input images by alpha blending. To improve the computational efficiency, reduced images are used for PCA and k-NN analysis. Experimental results showed that our method was more accurate comparing with the previous method with the improvement of the registration speed. Our stitching method could be usefully applied into the stitching of 2D or 3D multiple images.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1385-1391
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• 2015

A water reuse system was designed for a demonstration plant by combining fiber filtration and electrolysis. A discharged dye wastewater after treated with biomedia was used in this study. It was found that an additional removal of suspended solids (SS) was feasible with 2-stage filtration while electrolysis was not effective. Also, $COD_{cr}$ and $COD_{Mn}$ were not removed with 2 -stage filtration but electrolysis resulted in about 26.9% additional removal. This indicates that electrolysis play an important role in organic removal. Removal of T-N and T-P was negligible with 1 and 2-stage fiber filtration and low-level electrolyte. However, with 2000 ppm of electrolyte, their removal efficiencies were about 83.1 and 60%, respectively, suggesting that the removal rates are well associated with the electrolyte concentrations. With high-level electrolyte, colority was removed about 82% while chlorine ions were removed only about 10%. Therefore, to treat underground water containing high-level salinity in the follow-up study, based on the results in this paper, a combined system with selection of additional unit process and reverse osmosis will be designed.

• Transactions of Materials Processing
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• v.21 no.8
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• pp.499-505
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• 2012

The fuel cell is a very promising power generation system combining the benefits of extremely low emissions, high efficiency, ease of maintenance and durability. In order to promote the commercialization of fuel cells, a flexible forming process, in which a hyper-elastic rubber is adopted as a medium to transmit forming pressure, is suggested as an efficient and cost effective manufacturing method for fuel cell bipolar plates. In this study, the ability of this flexible forming process to produce the micro channel arrays on metallic bipolar plates was first demonstrated experimentally. Then, a finite element (FE) model was built and validated through comparisons between simulated and experimental results. The effects of key process parameters on the forming performance such as applied load and punch velocity were investigated. As a result, appropriate process parameter values allowing high dimensional accuracy without failure were suggested.