• 유통과학연구
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• 제12권2호
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• pp.59-71
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• 2014

Purpose - In recent years, many firms have attempted various approaches to cope with the continual increase of aviation transportation. The previous research into freight charge forecasting models has focused on regression analyses using a few influence factors to calculate the future price. However, these approaches have limitations that make them difficult to apply into practice: They cannot respond promptly to small price changes and their predictive power is relatively low. Therefore, the current study proposes a freight charge-forecasting model using time series data instead a regression approach. The main purposes of this study can thus be summarized as follows. First, a proper model for freight charge using the autoregressive integrated moving average (ARIMA) model, which is mainly used for time series forecast, is presented. Second, a modified ARIMA model for freight charge prediction and the standard process of determining freight charge based on the model is presented. Third, a straightforward freight charge prediction model for practitioners to apply and utilize is presented. Research design, data, and methodology - To develop a new freight charge model, this study proposes the ARIMAC(p,q) model, which applies time difference constantly to address the correlation coefficient (autocorrelation function and partial autocorrelation function) problem as it appears in the ARIMA(p,q) model and materialize an error-adjusted ARIMAC(p,q). Cargo Account Settlement Systems (CASS) data from the International Air Transport Association (IATA) are used to predict the air freight charge. In the modeling, freight charge data for 72 months (from January 2006 to December 2011) are used for the training set, and a prediction interval of 23 months (from January 2012 to November 2013) is used for the validation set. The freight charge from November 2012 to November 2013 is predicted for three routes - Los Angeles, Miami, and Vienna - and the accuracy of the prediction interval is analyzed using mean absolute percentage error (MAPE). Results - The result of the proposed model shows better accuracy of prediction because the MAPE of the error-adjusted ARIMAC model is 10% and the MAPE of ARIMAC is 11.2% for the L.A. route. For the Miami route, the proposed model also shows slightly better accuracy in that the MAPE of the error-adjusted ARIMAC model is 3.5%, while that of ARIMAC is 3.7%. However, for the Vienna route, the accuracy of ARIMAC is better because the MAPE of ARIMAC is 14.5% and the MAPE of the error-adjusted ARIMAC model is 15.7%. Conclusions - The accuracy of the error-adjusted ARIMAC model appears better when a route's freight charge variance is large, and the accuracy of ARIMA is better when the freight charge variance is small or has a trend of ascent or descent. From the results, it can be concluded that the ARIMAC model, which uses moving averages, has less predictive power for small price changes, while the error-adjusted ARIMAC model, which uses error correction, has the advantage of being able to respond to price changes quickly.

• 유통과학연구
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• 제12권10호
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• pp.99-108
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• 2014

Purpose - The goals of this study are the following. First, this study focused on customer satisfaction of in-flight service. Specifically, in-flight duty free items were considered because of their potential value related with the differentiated strategy of airline companies. Second, this study analyzed feasible strategies that would fence off the aversive attitudes of consumers toward innovation regarding in-flight duty free items. Third, this study strived to discover implicit routes related with the reactions of of consumers to innovation. Fourth, the construal level theory was applied to the context of in-flight service. Psychological distance is expected to promote acceptance of innovation for duty free items. Research design, data, and methodology - This study consisted of three experiments. All data were collected through the participation of university students. First, the experiment employed a 2×2 between-subject design. The first independent variable was temporal distance (long vs. short of navigation time). The second independent variable was innovativeness (innovative duty free items vs. typical items). Further, experiment 2 involved a 2×2 between-subject design. The first independent variable was social distance (typical vs. atypical stewardess image). The second was innovativeness that was based on a pattern similar to that of the prior experiment. The third experiment involved a 2×2×2 design. The first and second independent variables were temporal distance and item innovation, respectively, based on the method of experiment 1. The third independent variable was cognitive depletion (depletion vs. control condition). Results - Experiment 1 demonstrated that the innovation of duty free items would need to consider the journey time of the airline. Specifically, innovative items were preferred in case of a long journey; typical items, however, were liked in a short journey. Further, experiment 2 demonstrated that, in spite of a short journey, innovative items would be preferred if an atypical stewardess was serving. An atypical stewardess was linked with social distance, and the psychological effects would activate a creative and flexible mindset that would fit with innovative duty free items. The final experiment was accomplished for the examination of cognitive processing of psychological distance on innovation-acceptance. Specifically, if the effects were related with systematic processing, then cognitive effort would be needed. In contrast, if they were related with heuristic processing, then such efforts would not be required. The same pattern appeared under both cognitive depletion and control condition; therefore, the effects of psychological distance were implied to be heuristic processing. Conclusions - Managers need to consider the navigation time, stewardess concepts, and depletion of consumers as important factors for innovative strategy regarding in-flight service. Longer journeys are more successful for innovative trials. Further, a more atypical stewardess image is more successful for atypical service. Long navigation and unfamiliar stewardesses may activate creative and flexible thinking. Further, cognitive depletion of consumers is not a dominant factor of psychological distance effects, because the effects are not related with systematic processing, but with heuristic processing.

• 한국콘텐츠학회논문지
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• 제16권5호
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• pp.732-745
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• 2016

본 연구는 지방자치단체 조례분석을 통해 장애인생산품 우선구매 활성화방향을 제시하는데 목적이 있으며, 2015년 7월 현재 지방자치단체가 제정 또는 입법예고한 조례 44건을 조례의 각 항목을 분석하였다. 분석결과를 살펴보면 첫째, 전국 지자체 중 44개 지자체에만 조례가 제정되어(18.1%) 더 많은 지자체의 조례제정이 필요하다. 둘째, 조례의 구성내용 분석결과 조례의 목적 및 적용대상기관, 이행계획, 구매 협조 요청, 구매촉진 의무는 대부분의 지방차지단체에서 제시되고 있었다. 반면에 그 외 항목은 명시되지 않은 곳이 많았고 특히, 지자체장의 책무는 30개만 명시되어(68.1%) 있었다. 셋째, 상위 법령 위반(불일치) 조항이 있었다. 넷째, 이행계획 수립을 위한 위원회 설치에 관한 조항은 한 곳도 명시되지 않았다. 우선구매 확대를 위해 계획단계에서부터 학계, 현장, 장애인당사자가 포함된 위원회 설치의 검토가 필요하다. 다섯째, 적극적인 우선구매를 위한 조례 항목의 신설이 필요하며, 효과적인 생산 유통 판매 기반마련을 위한 규정이 필요하다. 마지막으로, 중앙정부가 지자체의 장애인생산품 우선구매 관련 조례와 실적 등을 모니터링하고 이를 개선해 나가기 위한 노력이 요구된다.

• 유통과학연구
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• 제16권3호
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• pp.69-77
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• 2018

Purpose - As more low cost carriers are introduced, the competition between the low cost carriers to become the nation's leading low cost carrier is also being intensified. The purpose of this study is to select various choice attributes for low cost carrier and figure out important factors that customers take into account for low cost carrier selection. The study also involves in establishing the relationship between perceived value, customer satisfaction, and customer behavior Intention, in an effort to identify choice attributes that are important to customers' low cost carrier. Research design, data, and methodology - To examine these research models, samples were collected from 247 peoples who visited In-Cheon international Airport during June, 2017. Results - The results of the study showed that, 'reservation service', 'airport service', 'in-flight service', and 'price' services have a significant effect on the perceived value of the choice attributes. While 'reservation service', 'airport service', 'in-flight service', and 'flight operation service' have a significant effect on the customer satisfaction of the choice attributes, perceived value has a significant effect on customer satisfaction. Perceived value has a significant effect on customer behavior intention. Finally, customer satisfaction has a significant effect on customer behavior intention. Conclusions - Flight operation service has no significant effect on perceived value of the choice attributes of low cost carriers, which indicates that the low cost carriers have not yet been well-established in the flight operation service sector. It seems likely that low cost carrier will be able to gain a competitive advantage over other companies if they expand their routes and improve the convenience of flight connections. In addition, the results show that the price service does not have a significant effect on customer satisfaction of the choice attributes of low cost carriers. From this, we may assume that the airline ticket prices of low cost carriers are already low, and the price cannot be a deciding factor in the competitive advantage of low cost carriers. To achieve higher customer satisfaction of the choice attributes, companies should strengthen the competitiveness of 'reservation service', 'airport service', 'in-flight service', and 'flight operation service'.

• 한국수산과학회지
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• 제32권3호
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• pp.338-344
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• 1999

Floating debris was recorded from a training ship, $\sharp$1 Kwanaksan, of Pukyong National University with about 10 knots speed at July 15th and 20th of 1997. The sampled area is the middle of southern sea of Korea, divided into 44 unit segments on survey routes. Debris fabrication materials were categorized with 6 items using the following; man-made or natural wood items, paper and cardboard, nylon netting and rope, styrofoam, plastics, floating metal and glass containers. All identified items within a 100 $\pm$ 2 m wide band were recorded but ignored if beyond this boundary. The results of distribution and transport of floating debris in the area are as follows: 1. The quantities of debris during the survey were distributed from $1.6\~369.7\;items/km^2$. The most obvious trend is the widespread distribution of all debris. The highest densities of all debris were discovered in the coastal waters of Namhae and Yokji island, and of about 50 km off from the southward of Yokji and about 74 km off from the eastward of Komun island. Especially many of small styrofoams within $\phi$20 cm were observed in these segments. 2. Styrofoams and plastics were composed of $83.5\%$ among all debris, next woods items, $9.8\%$. 3. The quantities, distribution shapes and composition of debris were varied as the observed duration and the natures of each items. 4. These phenomena are concluded that firstly they depend on the river discharges included debris due to precipitation falls, secondly inflow or dumping debris are drifting to the off-shore by Kuroshio currents present at their adjacent sea, But on the basis of the observed data it is difficult that source position, quantities and inflow items of debris are identified, and also the transport processes is pursue. further more surveys are continuously being investigated, and from this it is hoped that a much wider coverage can be achieved, perhaps on all sites of the Coast of Korea and contributed to the stationary area, finding of sources, removal method of debris and resistants of marine productivity.

• Strategy21
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• 통권42호
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• pp.53-82
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• 2017

Samuel Eliot Morison (1887-1976) was one of the pre-eminent historians of his generation. He was not only a famous historian at that time, but also was promoted to the rank of Admiral in U.S. Navy Reserve. Fifteen volume History of United States Naval Operations in World War II was published between 1947 and 1962, was not only a comprehensive report on the Navy's projection of power over two oceans, but a classic of historical literature that stands as the definitive treatment of it subject. Although he was fifty-five when war come to America in December 1941. Samuel Eliot Morison was determined to play a role. A professor at Harvard at the time, he joined volunteering for duty in the Navy. An experienced sailor, Professor Morison had earlier sailed that same routes taken by Christopher Columbus while researching his biography, Admiral of the Ocean Sea, which appeared in January 1942 th much acclaim and later got a Pulitzer Prize. Thus Morison plunged into the war, crossing the Atlantic aboard a destroyer. He assumed himself as "Parkman on the sea", tried to follow Parkman's historiographic method, not only participatory history but also literary style. And during writing History of United States Naval Operations in World War II, He emphasized two principles, publicity and objectivity. In terms of publicity, he always worried about who read history and why. In his pamphlet, "History as a Literary Art", he asserted it is useless if readers do not read a history which historians wrote. So he thought historians have forgotten that there is an art of writing of history. Therefore, he built his narratives around brightly rendered visuals and used the present tense to describe actions he witnessed firsthand, he wrote of the U.S. combat in very vividly. But strongly driven by publicity, he sometimes lost his balance in writing the naval history. For instance, the naval history became the focus of criticism for its prejudiced comments about the commanders. Also some reviewers asserted he did not secure the objectivity on writing the naval history. Although he sometimes deliberately torpedoed the objectivity of his work for strengthening publicity, by writing an extensive U.S. naval history, he introduced maritime history and naval history to the public widely. Until in early twentieth century, U.S. historians usually had been focusing their effort to the traditional areas, for example politic, economy, and etc. His intensive effort on the operations of U.S. Navy in World War II aroused a public interest in maritime and naval history. In conclusion, through using literary style and realistic narratives, historian Morison wrote a naval history for all the people which could appealed to the public.

• 한국대기환경학회지
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• 제34권2호
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• pp.321-330
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• 2018

Concentrations of the atmospheric radon and gaseous pollutants were measured at the Gosan site on Jeju Island from 2010 to 2015, in order to observe their time-series variation characteristics and examine the concentration change related to the airflow transport pathways. Based on the realtime monitoring of the atmospheric radon and gaseous pollutants, the daily mean concentrations of radon ($^{222}Rn$) and gaseous pollutants($SO_2$, CO, $O_3$, $NO_x$) were $2,400mBq\;m^{-3}$ and 1.3, 377.6, 41.1, 3.9 ppb, respectively. On monthly variations of radon, the mean concentration in October was the highest as $3,033mBq\;m^{-3}$, almost twice as that in July ($1,452mBq\;m^{-3}$). The diurnal variation of radon concentration shows bimodal curves at early morning (around 7 a.m.) and near midnight, whereas its lowest concentration was recorded at around 3 p.m. Several gaseous pollutants($SO_2$, CO, $NO_x$) showed a similar seasonal variation with radon concentration as high in winter and low in summer, whereas the $O_3$ concentrations had a bit different seasonal trend. According to the cluster back trajectory analysis, the frequencies of airflow pathways moving from continental North China, East China, Japan and the East Sea, the Korean Peninsula, and North Pacific Ocean routes were 36, 37, 10, 13, and 4%, respectively. When the airflow were moved to Jeju Island from continental China, the concentrations of radon and gaseous pollutants were relatively high. On the other hand, when the airflows were moved from North Pacific Ocean and East Sea, their concentrations were much lower than those from continental China.

• 대한환경공학회지
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• 제33권10호
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• pp.731-738
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• 2011

본 논문에서는 실험실적 규모의 순환형 회분식 반응기에서 수용액상 phenol을 처리하기 위해 $O_3/UV$ radiation, $O_3/Mg(OH)_2/UV$ radiation 그리고 $O_3/MgO/UV$ radiation 고급산화공정(AOPs)에 대한 연구를 수행하였다. 오존의 유량은 1.0 L/min, 오존 농도를 $150{\pm}10mg/L$로 일정하게 유지 하였으며, 산화반응에 나타나는 $COD_{Cr}$ 및 TOC를 각각 측정하였다. $20^{\circ}C$에서 $O_3/UV$ radiation, $O_3/Mg(OH)_2/UV$ radiation 그리고 $O_3/MgO/UV$ radiation에 대한 유사 1차 반응속도 상수는 각각 $9.31{\times}10^{-5}sec^{-1}$, $1.19{\times}10^{-4}sec^{-1}$ 그리고 $1.79{\times}10^{-4}sec^{-1}$, 활성화 에너지는 각각 $3.03kcal{\cdot}mol^{-1}$, $1.79kcal{\cdot}mol^{-1}$ 그리고 $4.23kcal{\cdot}mol^{-1}$ 로 나타났다. 수용액상에서 $Mg(OH)_2$와 MgO가 phenol의 분해와 COD의 제거에 현저한 촉진작용을 나타낸다는 것을 확인하였다. 이러한 실험 결과에 기초하여 $O_3/MgO/UV$ 시스템이 수용액상 phenol을 처리하기 위한 효율적이고 용이한 방법임을 제시하였다.

• 한국항해항만학회지
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• 제27권5호
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• pp.527-537
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• 2003

선박의 항행에 의해 발생되는 항주파의 특성은 선박의 속도와 수심 조건에 따라 크게 달라진다. 연안 항로에서 발생된 항주파는 주변 해안으로 전파됨에 따라 항만 내의 정온 수역을 교란하여 정박 중인 소형선박, 수영객 등에 돌발적이고도 심각한 위험을 가져다 줄뿐만 아니가 해안의 침식, 호안의 결괴 등의 피해를 주기도 한다. 지금까지 항주파에 관한 연구의 관심사는 일정 수심 조건에 대해 조파저항이나 조선에 미치는 영향을 분석하는 등 주로 조선공학도의 관점에서 검토가 대상이 되어 왔으며, 가변 수심을 가진 실제 해역에 있어서의 항주파 발생과 전파에 기인한 주변 해역의 영향은 그다지 검토되지 못하였다. 최근 고속선 등의 발달로 인해 천해역에서의 항주파로 인한 인근 해역의 피해가 더욱 우려되고 있는 추세이다. 따라서 실제 수역에서의 항주파의 발달과 그 전파과정은 조사할 필요가 있는 것이다. 본 연구에서는 연안해역의 얕고 복잡한 수로와 다양한 선속 조건에 대한 항주파의 발생 및 전파를 예측하기 위하여 고정 좌표계에서 Boussinesq 방정식을 토대로 항주파 수치예측 모형을 구축하였다. 제안된 모형은 수리모형실험 결과와의 비교를 통하여 검증하였으며, 또한 실제 수로를 토대로 한 가변 수심역에 개발된 모형을 적용하여 수신 변화 고려의 중요성을 확인하였다.

• 한국정보과학회논문지:정보통신
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• 제34권6호
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• pp.475-482
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• 2007

이동 무선 애드-혹 네트워크에서 이동 노드들은 일반적인 호스트 기능뿐만 아니라 이동 노드의 위치 변화에 따른 네트워크 토폴로지가 변화는 상태에서 데이타 패킷 전달의 역할도 수행하는 라우팅 기능을 수행한다. 이런 애드-혹 네트워크를 위한 라우팅 프로토콜이 여러 가지 있다. 본 논문에서는 여러 제안된 프로토콜 중에서 네트워크에서 라우팅으로 인한 프로토콜 오버헤드가 작은 요구/응답 방식으로 동작하는 DSR 프로토콜을 대상으로 성능을 향상시키는 새로운 경로 축소 방법을 제안했다. 기존 경로 축소 방법은 소스 경로 상에 있는 노드만이 경로 축소에 참여하는데 반해, 본 논문에서 소스 경로 밖에 있는 인접 노드들도 청취한 패킷으로부터 수집한 정보를 경로 캐쉬로 관리해서. 저장된 캐쉬 경로 정보를 토대로 진행 중인 연결에 대해 더 짧은 경로를 발견한 경우에 기존 경로 대신 새 경로를 사용하도록 경로 축소 작업을 수행하는 방법을 제시했다. ns2를 이용한 시뮬레이션 결과, 제안한 방법이 이동 노드의 위치 변화가 활발한 경우에 기존 방법보다 경로 축소 횟수가 많이 발생했고, 또한 토폴로지의 변화에 대해 신속한 경로 축소를 수행해서 패킷 전송 성공률도 높아졌음을 확인했다. 즉, 약간의 프로토콜 오버헤드를 치루고 노드의 이등성에 따라 두 배에서 다섯 배 정도의 경로 축소로 신속한 패킷 전송과 전체적인 노드의 에너지 소모를 줄일 수 있음을 확인하였다.