• Title/Summary/Keyword: limitation

Search Result 8,420, Processing Time 0.036 seconds

SCHEDULING REPETITIVE PROJECTS WITH STOCHASTIC RESOURCE CONSTRAINTS

  • I-Tung Yang
    • International conference on construction engineering and project management
    • /
    • 2005.10a
    • /
    • pp.881-885
    • /
    • 2005
  • Scheduling repetitive projects under limitations on the amounts of available resources (labor and equipment) has been an active subject because of its practical relevance. Traditionally, the limitation is specified as a deterministic (fixed) number, such as 1000 labor-hours. The limitation, however, is often exposed to uncertainty and variability, especially when the project is lengthy. This paper presents a stochastic optimization model to treat the situations where the limitations of resources are expressed as probability functions in lieu of deterministic numbers. The proposed model transfers each deterministic resource constraint into a corresponding stochastic one and then solves the problem by the use of a chance-constrained programming technique. The solution is validated by comparison with simulation results to show that it can satisfy the resource constraints with a probability beyond the desired confidence level.

  • PDF

Obstacle-avoidance Algorithm using Reference Joint-Velocity for Redundant Robot Manipulator with Fruit-Harvesting Applications

  • Y.S. Ryuh;Ryu, K.H.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
    • /
    • 1996.06c
    • /
    • pp.638-647
    • /
    • 1996
  • Robot manipulators for harvesting fruits must be controlled to track the desired path of end-effector to avoid obstacles under the consideration of collision free area and safety path. This paper presents a robot path control algorithm to secure a collision free area with the recognition of work environments. The flexible space, which does not damage fruits or branches of tree due to their flexibility and physical properties , extends the workspace. Now the task is to control robot path in the extended workspace with the consideration of collision avoidance and velocity limitation at the time of collision concurrently. The feasibility and effectiveness of the new algorithm for redundant manipulators were tested through simulations of a redundant manipulator for different joint velocities.

  • PDF

The Importance of Early Chronic Obstructive Pulmonary Disease: A Lecture from 2022 Asian Pacific Society of Respirology

  • Don D. Sin
    • Tuberculosis and Respiratory Diseases
    • /
    • v.86 no.2
    • /
    • pp.71-81
    • /
    • 2023
  • Chronic obstructive pulmonary disease (COPD) affects close to 400 million people worldwide. COPD is characterized by significant airflow limitation on spirometry. Most patients with COPD are diagnosed in their fifth or sixth decades of life. However, the disease begins much earlier. By the time airflow limitation is detected on spirometry, patients with COPD have lost close to 50% of their small airways. Thus, identification of patients with early COPD, defined as persons with preserved spirometry, who demonstrate pathologic or functional hallmarks of COPD, is essential for disease modification and ultimately disease elimination. This paper provides an up-to-date overview of the current case definition of early COPD, its importance, the novel technologies required for its detection in young adults and future directions in therapeutics for treatment.

Possibility and Limitation of Endoscopic Treatment in Early Gastric Signet Ring Cell Carcinoma (위의 인환세포암(Signet Ring Cell Carcinoma)에서 내시경적 절제술: 가능성과 한계점)

  • Sun Hyung Kang;Hyun Yong Jeong
    • Journal of Digestive Cancer Research
    • /
    • v.6 no.2
    • /
    • pp.55-58
    • /
    • 2018
  • Gastric signet ring cell carcinoma (SRC) is a poorly differentiated or undifferentiated cancer of the stomach. However, early gastric SRC showed lower LN metastasis in many studies, thus some endoscopists now regard early gastric SRC as a candidate for endoscopic treatment. But there are unsolved problems of the validity of endoscopic resection in early gastric SRC. In this review, we will comprehensively review the previous clinical studies and discuss the limitation of current studies and the possibility of endoscopic resection of early gastric SRC.

  • PDF

Analysis of soft deformation limitation of base-isolated structures

  • Jinwei Jiang;Baoyang Yang
    • Earthquakes and Structures
    • /
    • v.26 no.1
    • /
    • pp.1-15
    • /
    • 2024
  • Isolation technology has been proven effective in reducing the seismic response of superstructures, where most of the deformation is concentrated in the isolation layer. However, in cases of earthquakes with intensities surpassing the fortification level of the area, or severe near-fault earthquakes, the isolation layer may experience excessive deformation, resulting in damage to the isolation bearings or collisions with the retaining wall or surrounding buildings. In this study, a finite element model using ABAQUS is established and compared with experimental test results to deeply investigate the influence of limit devices on the isolation layer and its response to the superstructure. The findings reveal that a larger limiter stiffness and a smaller reserved gap can achieve a more effective limiting effect. Nevertheless, a smaller reserved gap and a larger limiter stiffness may result in increased response of the superstructure. Therefore, rational selection of the reserved gap and limiter stiffness is crucial to reduce the acceleration response.