A New Worker Policy for Self-Balancing Production Line with Stations

Hirotani, Daisuke,Morikawa, Katsumi,Takahashi, Katsuhiko Korean Institute of Industrial Engineers 2011 Industrial Engineeering & Management Systems Vol.10 No.3

In traditional production lines, such as assembly lines, each worker is usually assigned to a particular fixed work, and decreasing the task to master the assigned work is valuated. However, when an imbalance exists between workers' speeds, if a worker delays the overall work in the production line, the production rate of the particular line will also decrease. To avoid this problem, the "Self-Balancing Production Line" was introduced. In this type of production line, each worker is assigned work dynamically, and when specific conditions are satisfied, production remains balanced. Characteristics of these lines that can be preempted at any place have already been analyzed by some researchers. A previous paper examined the situation in which only a single worker can process one machine and cannot preempt processing, and the improved policy of an ordinary selfbalancing production line, which specifies which stations workers can process and how workers can behave. This policy achieveda high production rate with only four stations and two workers (Buzacott, 2002). In that paper, worker processing stations and the behavior of a specific worker were limited, andthe paper focused only on specific stations and workers. Therefore, it is not applicable to any worker sequence. In this paper, we focus on other ways to decrease cycle time. In this kind of line, a worker processes at his or her speed. Therefore, if a worker is assigned stations according to his or her speed, the line can decrease cycle time. To do so, we relax the assumptions of this type of line and set a new condition. Under these conditions, we compare our results to the results of previous papers.

댐 저수지에서 alkaline phosphatase 활성의 수직변화와 미생물 요인들과의 상관관계

( Hirotani Hiroshi ),( Ayumi Nakagawa ),( Hisanori Kagawa ) 한국하천호수학회 2004 생태와 환경 Vol.37 No.4

The alkaline phosphatase activity (APA) of two dam reservoirs and inflowing streams were measured monthly in 2000. During summer months in 2001, the vertical profiles of APA and related parameters were also examined in one of the reservoirs. The APA was relatively high during the summer season in the epilimnion while it was almost invariable in the hypolimnion. A small increase in APA was observed at just above the bottom. The APA fluctuation was independent of the concentration of soluble reactive phosphorus. It was assumed that APA is not indicative of the phosphorus availability status. An examination of size-fractionated samples suggested that APA in reservoirs was attached to particles larger than 0.4 ㎛, whereas in streams it existed in a dissolved form. There was a positive significant correlation between chlorophyll α concentration and APA in the photic zone. In the aphotic zone, APA correlated positively with the colony count of heterotrophic bacteria, but not with microscopic total bacterial counts.

Influence of Time to Walk Back and Comparing for the Self-balancing Production Line

Hirotani, Daisuke,Myreshka, Myreshka,Morikawa, Katsumi,Takahashi, Katsuhiko Korean Institute of Industrial Engineers 2005 Industrial Engineeering & Management Systems Vol.4 No.1

In traditional production lines, such as assembly lines, each worker is usually assigned to a fixed task, which is beneficial since it reduces the amount of training needed for workers to master their assigned tasks. However, when workers complete their tasks at different speeds, the slowest worker will determine the overall pace of the production line and limit production. To avoid this problem, the self-balancing production line was introduced. In this type of production line, each worker works dynamically, thus they can maintain balanced production. Previous research analyzing the performance of these lines has ignored the walk-back time associated with dynamic workers. U-shaped production lines have also been analyzed and policies for such lines have been proposed. However, the walk-back time cannot be ignored in practice, and research taking this factor into account is needed to enable balanced production and thus the maximum production rate. In this paper, we propose production policies for a production line with the walk-back time taken into account, and define and analyze the conditions for self-balancing. Furthermore, we have compared the performance of such a line with that of other production lines under the same conditions, and the results show the superiority of this line in certain cases.

Vertical Profiles of Alkaline Phoshphatase Activity in Dam Reservoirs and its Relation with Microbial Parameters

Hirotani, Hiroshi,Ayumi Nakagawa,Hisanori Kagawa 한국수생태학회(구 한국하천호수학회) 2004 생태와 환경 Vol.37 No.4

A New Worker Policy for Self-Balancing Production Line with Stations

Daisuke Hirotani,Katsumi Morikawa,Katsuhiko Takahashi 대한산업공학회 2011 Industrial Engineeering & Management Systems Vol.10 No.3

In traditional production lines, such as assembly lines, each worker is usually assigned to a particular fixed work, and decreasing the task to master the assigned work is valuated. However, when an imbalance exists between workers" speeds, if a worker delays the overall work in the production line, the production rate of the particular line will also decrease. To avoid this problem, the "Self-Balancing Production Line" was introduced. In this type of production line, each worker is assigned work dynamically, and when specific conditions are satisfied, production remains balanced. Characteristics of these lines that can be preempted at any place have already been analyzed by some researchers. A previous paper examined the situation in which only a single worker can process one machine and cannot preempt processing, and the improved policy of an ordinary self-balancing production line, which specifies which stations workers can process and how workers can behave.This policy achieveda high production rate with only four stations and two workers (Buzacott, 2002). In that paper, worker processing stations and the behavior of a specific worker were limited, andthe paper focused only on specific stations and workers. Therefore, it is not applicable to any worker sequence. In this paper, we focus on other ways to decrease cycle time. In this kind of line, a worker processes at his or her speed. Therefore, if a worker is assigned stations according to his or her speed, the line can decrease cycle time. To do so, we relax the assumptions of this type of line and set a new condition. Under these conditions, we compare our results to the results of previous papers.

Analysis of Y-Shaped Self-Balancing Line with Walk-Back and Travel Time

Daisuke Hirotani,Katsumi Morikawa,Katsuhiko Takahashi,Keisuke Nagasawa 대한산업공학회 2018 Industrial Engineeering & Management Systems Vol.17 No.2

In traditional assembly lines, each worker is usually assigned a fixed work station. However, when an imbalance be-tween workers’ speeds exists, the production rate of the line decreases. To avoid this problem, the “self-balancing line” was introduced. Although typically assumed to be serial, recent studies have assumed a Y-shaped type line (with two sub-lines that then combine). However, as the workers take more time to travel in this arrangement, walk-back and travel time must be considered. Furthermore, when considering more than two workers, the condition that balanc-es the line changes according to the length of the sub-lines. In this paper, the authors first derive the condition that balances the line for three workers, and then analyze the characteristics of this type of line. Finally, the authors find the condition that balances the line for n workers

일본의 혐한 담론에 보이는 인종주의와 그 특징

히로타니마미 ( Hirotani Mami ),박용구 ( Park Yong-koo ) 한국일어일문학회 2016 日語日文學硏究 Vol.98 No.2

2010년을 전후 해 일본사회에서 배타적이고 차별적인 발언을 동반한 혐한 데모가 행해지기 시작했다. 그 주장들을 살펴보면 흥미롭게도 과거에 보이던 정치적, 역사적 혐한 감정과는 달리 인종주의(racism)적 성격이 짙게 깔려 있다. 그럼에도 불구하고 최근의 혐한 현상을 인종주의적 시각에서 구체적, 체계적으로 분석한 연구가 눈에 띄지 않는다. 따라서 이 논문에서는 이런 일본의 혐한 현상을 「생물학적 인종주의」와 「문화적 인종주의」라는 두 가지의 인종의적 관점에서 분석해 보고자 한다. 연구방법으로는 혐한 담론의 진원지라 할 수 있는 만화·인터넷·인터뷰의 내용분석을 활용하기로 한다. 2000년대부터 인종주의적인 성질을 띠기 시작한 혐한 담론 속에는 「불결하다」,「저능하다」, 「추하다」,「범죄가 많다」와 같이 한민족을 열등시 하는 생물학적 인종주의와「사회 복지 특권을 받고 있다」,「일본 문화를 파괴한다」와 같이 주로 재일코리안을 차별의 대상으로 한 문화적 인종주의가 동시에 보인다. 그런데 생물학적 인종주의 담론의 대부분은 인터넷 상에서 보이고 문화적 인종주의 담론은 만화, 인터넷, 인터뷰 모두에 걸쳐 나타나고 있다. 즉, 인터넷이라는 익명성 높은 매체에서는 생물학적 인종주의가 적나라하게 보이는 반면 익명성이 낮은 만화나 인터뷰에서는 생물학적 인종주의는 그다지 보이지 않는 것이다. 인터뷰의 경우에는 오히려 생물학적 인종주의를 부정적으로 여기는 경우도 많이 있었다. 구미의 경우와 마찬가지로, 이처럼 일본에서도 두 가지의 인종주의가 공존하는 가운데 공공연한 생물학적 인종주의보다는 문화적 인종주의의 담론이 두드러지게 나타나고 있음을 확인할 수 있었다. Anti-Korean protests are being staged in Japan, where protesters make hateful and discriminatory remarks to and about Koreans. This anti-Korean sentiment is now causing problems in terms of fueling racism. In order to address the situation, we first need to understand how racism is expressed in an anti-Korean sentiment. To this end, the article analyzed the contents of cartoons on the Internet and interviews concerning biological racism and cultural racism in an attempt to examine the characteristics of racist remarks made by the anti-Korean Japanese. Anti-Korean remarks include biological and cultural racist remarks. The scientific racist remarks include the expressions "dirty," "retarded," "ugly," and "rough" to describe Koreans as inferior to the Japanese. Cultural racist remarks primarily target the Korean-Japanese with claims such as "The Korean-Japanese receive social welfare unfairly" and "They destroy Japanese culture." It turns out that the scientific racist remarks were mostly found on the Internet and not during interviews. Cultural racist remarks were found in cartoons, the Internet, and interviews. Although scientific racist remarks have a strong presence on the Internet because of its anonymity, they are rarely found in other forms of media that are not anonymous. As a result, as is seen in the United States and European countries, two kinds of racism co-exist in Japan, where scientific racism publicly disappears but the concepts of cultural racism have become relatively widespread.

Influence of Time to Walk Back and Comparing for the Self-balancing Production Line

Daisuke Hirotani,Myreshka,Katsumi Morikawa,Katsuhiko Takahashi 대한산업공학회 2005 Industrial Engineeering & Management Systems Vol.4 No.1

Influence of Time to Walk Back and for the Self-balancing Production Line Comparing

Daisuke Hirotani,Myreshka,Katsumi Morikawa,Katsuhiko Takahashi 대한산업공학회 2005 Industrial Engineeering & Management Systems Vol.4 No.1

In traditional production lines, such as assembly lines, each worker is usually assigned to a fixed task,which is beneficial since it reduces the amount of training needed for workers to master their assigned tasferent speeds, the slowest worker will determine the overall pace of the production line and limit production. To avoid this problem, the self-balancing production line was introduced. In this type of production line, each worker works dynamically, thus they can maintain balanced production. Previous research analyzing the performance of these lines has ignored the walk-back time asociated with dynamic workers. U-shaped production lines have also been analyzed and policies for such lines have been proposed. However, the walk-back time cannot be ignored in practice, and research taking this factor into account is needed to enable balanced production and thus the maximum production rate. In this paper, we propose production policies for a production line with the walk-back time taken into account, and define and analyze the conditied the performance of such a line with that of other production lines under the same conditions, and the results show the superiority of this line in certain cases.

Developing a Two-Stage Supply Chain Model using a Discrete Time Markov Chain Model during Supply Chain Disruptions

Suchera Putthakosa,Daisuke Hirotani 대한산업공학회 2023 Industrial Engineeering & Management Systems Vol.22 No.4