Study of Liquefaction Damages of Quay-Walls and Breakwaters During Kobe Earthquake

During Kobe Earthquake, very extensive damages of harbor facilities such as quay-wall and breakwater occurred in Kobe Port and also along the coastal areas between Kobe and Osaka cities. Major causes of the damages were the liquefaction of sands underlying and behind the concrete caisson and also strong earthquake shaking force on the caisson. The degree of damage varied considerably depending on location and also on the size of structure. In order to understand the mechanism of damage as well as the factors that controlled the degree of damage, it was necessary to examine and analyze the case records of damages of these structures. This paper describes the result of such study on liquefaction damage of quay-walls and breakwaters. Through the study, it was found that the movement of sand at shallow depth below the caisson base is mainly responsible for a large settlement of caisson, but the mode of deformation is different between quay wall and breakwater. Also an effective stress liquefaction analysis was performed on the damaged quay-walls and breakwaters in order to check the applicability of effective stress liquefaction analysis on damage assessment. It was found that the effective stress analysis may be used to establish the overall trend of damage variation with the intensity of seismic motion, but problems exist in setting the dynamic parameters for the analysis, such as damping parameters, in order to obtain a reliable result

Investigation into the multiple recent sinkholes in Pokhara, Nepal

Since November 2013, numerous sinkholes have been forming in the Armala area of Pokhara Valley, Central Nepal, posing serious threat to local residents. In order to provide countermeasures for reducing sinkhole risk, detailed investigations into the cause and the formation mechanism of the sinkholes are crucial. Preliminary surveys were conducted in June 2014 and November 2014. Comparison of photos, taken in the two surveys, clearly indicates not only the formation of new sinkholes, but also the re-activation of filled sinkholes. By means of dynamic cone penetration tests and surface wave investigations, qualitative characterization of the soil profile was attained, and shallow weak soil layers which are believed to be the location for future sinkholes could be identified. On the basis of the preliminary field investigation, possible sinkhole formation mechanisms are considered. A risk of sinkhole does not seem to disappear as white turbid water continuously springs. It indicates that the internal erosion of white clayey silt layer is still in progress. In August 2015, a boring was carried out beside one of the largest sinkholes. The overall structure of ground layers was first revealed and a 2.5m high cavity at 7.5-10m deep from the ground surface was found within a thick white clayey silt layer. Further ground investigations including surface wave exploration were conducted in December 2015 and the results are reported

Ownership and control in a competitive industry

We study a differentiated product market in which an investor initially owns a controlling stake in one of two competing firms and may acquire a non-controlling or a controlling stake in a competitor, either directly using her own assets, or indirectly via the controlled firm. While industry profits are maximized within a symmetric two product monopoly, the investor attains this only in exceptional cases. Instead, she sometimes acquires a noncontrolling stake. Or she invests asymmetrically rather than pursuing a full takeover if she acquires a controlling one. Generally, she invests indirectly if she only wants to affect the product market outcome, and directly if acquiring shares is profitable per se. --differentiated products,separation of ownership and control,private benefits of control

Efficient computation of upper bounds for the disjunctively constrained knapsack problem

The paper introduces efficient methods for computing upper bounds values for the disjunctively constrained knapsack problem

Efficient computation of upper bounds for the disjunctively constrained knapsack problem

ナップサック問題(knapsack problem) は情報科学の分野における基礎的な問題で, これまでに多 くの研究がある．また，ナップサック問題に制約を加えた問題も多数存在する．本論文ではその ひとつである排他制的付きナップサック問題(disjunctively constrained knapsack problem) を対 象とする．これは，同時に選択できないアイテムに関する制約(排他制約) と容量制約を満たすよ うにいくつかのアイテムを選択するとき，選択したアイテムの価値の合計を最大化する問題であ る．これに対し，クリークを用いた上界値計算法を提案する．本計算法により大規模な問題例や 辺密度の高い問題例に対して高速に上界値を計算できることを計算実験により確認した

A pattern-based reformulation for the one-dimensional bin packing with variabile pattern processing time

In the one-dimensional packing problem with variable pattern processing time, we extend the classical packing definition by introducing a scheduling perspective: each item is provided with a due date, and a pattern-dependent time to process each bin is taken into account. In order to concurrently reduce the material waste and the delay costs, both not negligible in several real contexts, we require the minimization of a convex combination of the number of used bins and maximum lateness. In this paper we present a new extended pattern-based reformulation for this problem and a dynamic programming algorithm to solve the corresponding quadratic pricing problem. Preliminary computational results are given to analyze the quality of the continuous relaxation

A computational study of exact knapsack separation for the generalized assignment problem

Generalized assignment problem, Cutting plane algorithm, Exact separation,