• 한국컴퓨터정보학회논문지
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• 제23권9호
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• pp.35-42
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• 2018

In this paper, we propose an optimal streaming service method based on Hybrid CDN/P2P architecture. Recently, video streaming utilizes a CDN (Content Delivery Network) operation technique based on a Proxy Server, which is an end node located close to a user. However, since CDN has a fixed network traffic bandwidth and data information exchange among CDNs in the network is not smooth, it is difficult to guarantee traffic congestion and quality of image service. In the hybrid CDN/P2P network, a data selection technique is used to select only the data that is expected to be continuously requested among all the data in order to guarantee the QoS of the user who utilizes the limited bandwidth efficiently. In order to search user requested data, this technique effectively retrieves the storage information of the constituent nodes of CDN and P2P, and stores the new image information and calculates the deletion priority based on the request possibility as needed. Therefore, the streaming service scheme proposed in this paper can effectively improve the quality of the video streaming service on the network.

• 농업과학연구
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• 제45권4호
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• pp.811-821
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• 2018

This study focused on the improvement of blueberry delivery service using pre-cooled ice and $SO_2$ pads to prevent an increase in the fruit temperature as well as decay. To maintain the fruit quality during low temperature storage, the effect of a $SO_2$ pad and modified atmosphere packaging was also examined. Harvested blueberries were precooled at $15^{\circ}C$, sorted, and packaged. And the fruits were placed in a similar environment as that for the parcel service. Part of the fruits were stored at $0^{\circ}C$ for long term storage. The air temperature in the delivery box increased along with an increase in the simulated delivery time regardless of the treatment. However, the rate of temperature increase was lower in the ice pad treatment. No significant difference was not found after 48 h. The oxygen concentration in the box ranged between 10.5 - 14.5% in the ice pad treatment, which was higher than that of the untreated control (7.5 - 11.9%) whereas the $CO_2$ concentration was lower in the ice pad treatment. No differences were found in the occurrence of off-flavor, decay, and sensory quality loss during the 48 hours of the parcel service simulation. The combined treatment of the $SO_2$ pad and modified atmosphere packaging (MAP) using a perforated film increased the shelf-life of the blueberry fruits, the overall quality such as firmness, and the soluble solid content was not different between the treatments except for the decay incidence. No decayed fruit was found in the combined treatment. However, the percentage of decayed fruit in the control was 25% on day 15 of storage and 75% on day 33 of storage, respectively.

• Journal of Communications and Networks
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• 제18권3호
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• pp.375-386
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• 2016

Most existing studies on broadcast services in orthogonal frequency division multiplexing (OFDM) systems have focused on how to allocate the transmission power to the subcarriers. However, because a broadcasting system must guarantee quality of service to all users, the performance of the broadcast service dominantly depends on the channel state of the user who has the lowest received signal-to-noise ratio among users. To reduce the effect of the worst user on the system performance, we propose a joint delivery scheme of unicast and broadcast transmissions in OFDM systems with broadcast and unicast best-effort users. In the proposed joint delivery scheme, the BS delivers the broadcast information using both the broadcast and unicast subcarriers at the same time in order to improve the performance of the broadcast service. The object of the proposed scheme is to minimize the outage probability of the broadcast service while maximizing the sum-rate of best-effort users. For the proposed joint delivery scheme, we develop an adaptive power and subcarrier allocation algorithm under the constraint of total transmission power. This paper shows that the optimal power allocation over each subcarrier in the proposed scheme has a multi-level water filling form. Because the power allocation and the subcarrier assignment problems should be jointly solved, we develop an iterative algorithm to find the optimal solution. Numerical results show that the proposed joint delivery scheme with adaptive power and subcarrier allocation outperforms the conventional scheme in terms of the outage probability of the broadcast service and the sum-rate of best-effort users.

• 경영과정보연구
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• 제28권4호
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• pp.175-197
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• 2009

인터넷쇼핑몰과 관련한 많은 연구들이 전자상거래의 서비스품질을 평가하는 기준을 세우고 인터넷쇼핑몰에 영향을 미치는 요인을 파악하며 전자상거래에서의 요인들이 쇼핑몰과는 어떠한 관계에 있는가에 대해 초점을 둔 연구들이었다. 그러나 대부분의 연구는 서비스품질 모델이나 기본적인 기능적 차원에 대해 이루어졌다. 이러한 이유로 소비자들의 인터넷쇼핑몰에 영향을 주는 개별적 충성도와 잠재적인 인지성에 대한 변수들간의 통합된 구조적 관계의 확인이 요구된다. 본 연구의 목적은 서비스 품질에 관한 선행연구를 기반으로 인터넷 쇼핑몰이 갖는 기업 이미지, 시스템 품질, 서비스 품질, 배송 품질 등을 고려한 실증분석을 통해 고객 만족도 및 충성도에 영향을 미치는 요인들을 규명하고자 한다. 분석결과 주요 시사점을 정리하면 다음과 같다. 첫째, 인터넷 쇼핑몰의 기업 이미지는 시스템 품질과 배송 품질에 긍정적인 영향을 미치는 것으로 나타났다. 인터넷 쇼핑몰을 운영하는 기업의 이미지에 따라 인터넷 쇼핑몰의 웹 사이트와 배송 서비스가 달라질 것이라는 고객의 인지를 의미한다고 볼 수 있다. 둘째, 기업 이미지가 서비스 품질에 미치는 영향은 통계적으로 유의하지 못한 것으로 나타났다. 기업의 이미지와 실제 인터넷 쇼핑몰이 제공하는 서비스의 품질은 구분된다는 점을 의미하는데, 서비스 품질이 우수할 경우 이는 곧 기업의 좋은 이미지를 구축하는 결과를 낳게 될 것으로 추정된다. 셋째, 인터넷 쇼핑몰의 물류 서비스인 배송 품질은 서비스 품질에 긍정적인 영향을 미치는 것으로 나타났다. 넷째, 시스템 품질은 서비스 품질에 통계적으로 유의한 영향을 보이지 않았다. 인터넷 쇼핑몰의 웹 사이트 구성이나 거래탐색의 편리성, 인터페이스 성능 등 기술적 특성은 인터넷 쇼핑몰이 제공하는 서비스의 품질과는 구분된다는 점을 의미한다. 마지막으로, 인터넷 쇼핑몰의 서비스 품질은 선행연구에서와 같이 고객 만족도에 긍정적 영향을 미치는 것으로 나타났으며, 고객 만족도는 고객 충성도에 긍정적 영향을 미치는 것으로 확인되었다.

• 한국의료질향상학회지
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• 제5권2호
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• pp.202-215
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• 1998

Purpose : To shorten processing time for variety of medical affairs of the patient at the outpatient clinic of a big hospital is very important to qualify medical care of the patient. Therefore, patient's waiting time for drug delivery after doctor's prescription is often utilized as a strong tool to evaluate patient satisfaction with a medical care provided. We performed this study to investigate factors influencing patient satisfaction related with waiting time for drug delivery. Methods : The data were collected from July 21 to August 12, 1998. A total 535 patients or their families who visited outpatient clinics of Inha University Hospital were subjected to evaluate the drug delivery time and the level of their satisfaction related, which were compared with those objectively evaluated by Quality Improvement Team. The reliability of the scale was tested with Cronbach's alpha, and the data were analyzed using frequency, t-test, ANOVA, correlation analysis and multiple regression. Results : The mean drug delivery time subjectively evaluated by the patient (16.1 13.0 min) was longer than that objectively evaluated (10.9 7.6 min) by 5.2 min. Drug delivery time objectively evaluated was influenced by the prescription contents, total amount or type of drug dispensed, etc, as expected. The time discrepancy between two evaluations was influenced by several causative factors. One of those proved to be a patient's late response to the information from the pharmacy which the drug is ready to deliver. Interestingly, this discrepancy was found to be more prominent especially when waiting place for drug delivery was not less crowded. Other factors, pharmaceutical counseling at the pharmacy, emotional status or behavior of a patient while he waits for the medicine, were also found to influence the time subjectively evaluated. Regarding the degree of patient satisfaction with the drug delivery, majority of patients accepted drug delivery time with less than 10 min. It was also found to be influenced by emotional status of the patient as well as kindness or activity of pharmaceutical counselor. Conclusion : The results show that, besides prescription contents, behavior pattern or emotional status of a patient, environment of the waiting place, and quality of pharmaceutical counseling at the pharmacy, may influence the patient's subjective evaluation of waiting time for drug delivery and his satisfaction related with the service in the big hospital. In order to improve patient satisfaction related with waiting time for drug delivery, it will be cost effective to qualify pharmaceutical counseling and information system at the drug delivery site or waiting place rather than to shorten the real processing time within the pharmacy.

• 한국융합학회논문지
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• 제9권12호
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• pp.239-250
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• 2018

본 연구는 한국과 중국 소비자들 간의 배달음식 앱에 대한 고객만족과 서비스 품질 요소의 영향력 정도를 분석하고자 하였다. 이러한 연구목적을 달성하기 위해서 MOBISQUAL이란 모바일 인터넷 서비스 품질 측정 도구를 통해 가설구조의 모형을 설정하였다. 연구결과, 한국소비자는 유희성과 충족성이 고객만족에 대해 긍정적인 영향을 미치는 것으로 나타났으며, 중국 소비자는 유희성, 유용성, 개인화, 디자인, 용이성, 안전성이 고객만족에 대해 긍정적인 영향을 미치는 것으로 나타났다. 본 연구결과는 한국과 중국 소비자들에게 배달음식 앱이 고객만족에 대한 영향을 미치는 요소 간의 차이가 있음을 발견하였고 이를 통해 관련 기업에서 고객만족을 위해 고려해야할 부분을 제시했다는데 의의가 있다.

• 품질경영학회지
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• 제33권4호
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• pp.12-20
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• 2005

Supply chain management is a total systems approach to delivering manufactured products to the end customer. Using information technology to coordinate all elements of the supply chain from parts suppliers to retailers achieves a level of integration that is a competitive advantage not available in traditional logistics systems. On the other hand, service chain management is an analogous systems approach that is especially suitable for delivering mobile services such as parcel delivery, cable installation, and home health care. The key elements that distinguish service supply chain management from supply chain management are bidirectional optimization, management of productive capacity, and management of perishability. The purpose of this study is to maintain the construction of service chain management by proving that service quality in after-sales service can be improved through service chain management. First of all, supply chain management, service quality, and service chain management were introduced in theoretical research. In empirical research, it was selected the domestic enterprise that produce electronic appliances with after-sales service, and some customers using the enterprise's after-sales service in the metropolitan area were selected as a sample by convenience sampling method and examined.

• 한국산업정보학회논문지
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• 제26권6호
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• pp.35-46
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• 2021

본 연구는 4차 산업혁명시대와 Covid 19로 인해 비대면 라이프스타일이 가속화됨에 따라 배달 앱을 이용하는 사용자의 행태를 분석하였다. 구체적으로 본 연구는 배달 앱 서비스를 이용하는 고객의 지각된 서비스 품질이 전환비용, 고객 만족과 지속적 사용의도에 미치는 영향을 살펴보고, 그 결과를 토대로 배달 앱을 이용하는 이용자(고객), 배달 앱에 가입하여 운영하는 입점자(음식점), 그리고 고객과 음식점을 연결하여 주는 플랫폼(배달의 민족 등)에 유용한 정보와 시사점을 제공하는 것이 주요 목적이다.

• 산업경영시스템학회지
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• 제46권2호
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• pp.160-167
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• 2023

This study focuses on the development of a Last-Mile delivery service using unmanned vehicles to deliver goods directly to the end consumer utilizing drones to perform autonomous delivery missions and an image-based precision landing algorithm for handoff to a robot in an intermediate facility. As the logistics market continues to grow rapidly, parcel volumes increase exponentially each year. However, due to low delivery fees, the workload of delivery personnel is increasing, resulting in a decrease in the quality of delivery services. To address this issue, the research team conducted a study on a Last-Mile delivery service using unmanned vehicles and conducted research on the necessary technologies for drone-based goods transportation in this paper. The flight scenario begins with the drone carrying the goods from a pickup location to the rooftop of a building where the final delivery destination is located. There is a handoff facility on the rooftop of the building, and a marker on the roof must be accurately landed upon. The mission is complete once the goods are delivered and the drone returns to its original location. The research team developed a mission planning algorithm to perform the above scenario automatically and constructed an algorithm to recognize the marker through a camera sensor and achieve a precision landing. The performance of the developed system has been verified through multiple trial operations within ETRI.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.3904-3917
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• 2017

IP multimedia subsystem (IMS) is an open standardized architecture for delivering multimedia service over IP network in a route-agnostic manner. With the increasing popularity of conversational class service, the delivery of a traffic flow with a certain bandwidth demand over a single network path is either not possible or not cost-effective. Multipath transmission is considered to be a promising solution to provide high-quality delivery service. This paper proposes a software defined service overlay network (SDSON) based multipath transmission framework for IMS, which is complementary to existing network architecture. The framework transforms original two-party session negotiation into three-party session negotiation that supports participants to negotiate multipath transmission capacity and path information by signaling message. Based on existing IETF standards, SIP and SDP are scalable to support these functions. Finally, the proposed framework is fully implemented on open source platform and examined by experiments. Experimental results show that multipath-enabled IMS is an effective way to improve the delivery performance of conversational class service.